The month of July was somewhat a tale of two months in one. The first half was most notable for their unseasonably warm temperatures and relatively dry conditions. The second half saw a few days of heat but for the most part was considerably cooler and wetter.
Thornton saw an average temperature for the month of 73.5 degrees. Out at Denver International Airport where the Mile High City’s official readings are taken, the month saw an average of 75.3 degrees. Long term, the month of July sees an average of 74.2 degrees in Denver so while Thornton was cooler than that, Denver was warmer.
Thornton had its highest temperature reading of 99.9 degrees on the 19th and its coldest of 47.7 degrees on the 1st. Denver saw its warmest reading of 99 degrees on the 3rd and its coldest of 47 degrees on the 1st.
In terms of precipitation, Denver’s long term July average is 2.16 inches. Thornton easily bested that number with 3.66 inches in our rain bucket. The Mile High City fell well short with only 1.03 inches.
Thornton, Colorado’s July 2018 temperature summary. (ThorntonWeather.com)Thornton, Colorado’s July 2018 precipitation summary. (ThorntonWeather.com)
CLIMATE REPORT
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
305 PM MDT WED AUG 1 2018
...................................
...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF JULY 2018...
CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2018
WEATHER OBSERVED NORMAL DEPART LAST YEAR`S
VALUE DATE(S) VALUE FROM VALUE DATE(S)
NORMAL
................................................................
TEMPERATURE (F)
RECORD
HIGH 105 07/20/2005
LOW 42 07/04/1903
07/31/1873
HIGHEST 99 07/03 99 0 100 07/19
07/06
LOWEST 47 07/01 51 -4 51 07/01
AVG. MAXIMUM 90.2 89.4 0.8 91.5
AVG. MINIMUM 60.3 58.9 1.4 61.3
MEAN 75.3 74.2 1.1 76.4
DAYS MAX >= 90 19 16.0 3.0 20
DAYS MAX <= 32 0 0.0 0.0 0
DAYS MIN <= 32 0 0.0 0.0 0
DAYS MIN <= 0 0 0.0 0.0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 6.41 1965
MINIMUM 0.01 1901
TOTALS 1.03 2.16 -1.13 0.47
DAILY AVG. 0.03 0.07 -0.04 0.02
DAYS >= .01 8 8.3 -0.3 6
DAYS >= .10 3 4.3 -1.3 3
DAYS >= .50 0 1.4 -1.4 0
DAYS >= 1.00 0 0.7 -0.7 0
GREATEST
24 HR. TOTAL 0.43 07/23 TO 07/23
SNOWFALL (INCHES)
TOTAL 0.0 0.0
RECORDS
TOTAL 0.0
DEGREE_DAYS
HEATING TOTAL 0 6 -6 0
SINCE 7/1 0 6 -6 0
COOLING TOTAL 326 289 37 360
SINCE 1/1 615 444 171 533
FREEZE DATES
RECORD
EARLIEST 09/08/1962
LATEST 06/08/2007
EARLIEST 10/07
LATEST 05/05
.................................................................
WIND (MPH)
AVERAGE WIND SPEED 10.1
RESULTANT WIND SPEED/DIRECTION 2/138
HIGHEST WIND SPEED/DIRECTION 47/140 DATE 07/02
HIGHEST GUST SPEED/DIRECTION 64/150 DATE 07/02
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.50
NUMBER OF DAYS FAIR 10
NUMBER OF DAYS PC 20
NUMBER OF DAYS CLOUDY 1
AVERAGE RH (PERCENT) 50
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORMS 13 MIXED PRECIP 0
HEAVY RAIN 3 RAIN 5
LIGHT RAIN 11 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 0
HEAVY SNOW 0 SNOW 0
LIGHT SNOW 0 FOG W/VIS <=1/4 MILE 3
FOG 8 HAZE 5
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
August 5 to August 11: This week in Denver weather history
As we enter August the weather typical is a bit calmer as the atmosphere settles down. However our look back at this week in Denver weather history shows that Mother Nature can still visit plenty of excitement on us.
From the National Weather Service:
5
In 1881…the low temperature cooled to only 76 degrees…the record high minimum temperature for the month.
In 1889…southwest winds were sustained to 42 mph.
In 1918…hail pelted the city…but was light and caused no damage. Precipitation totaled 0.25 inch. Northwest winds were sustained to 31 mph.
In 1964…lightning struck two boys in Denver while playing ball. One was treated and released from the hospital…but the other boy suffered second degree electrical shock and cardiac arrest and was hospitalized in critical condition for several days.
In 1969…two tornadoes touched down briefly in an open field southeast of Buckley Field in Aurora. No damage was reported.
In 1970…heavy rain in the Indian Hills area in the foothills west of Denver caused flash flooding…which washed out roads and damaged other property. Hail accumulated to a 3 inch depth with stones up to golf ball size; however…most of the damage was from flooding.
In 1982…2.38 inches of rain fell in an hour in Arvada… Causing minor flooding on Ralston Creek. In Westminster… 1 1/2 inches of rain fell…causing damage to streets and culverts. In addition…lightning caused some minor power outages across metro Denver.
In 1983…very heavy thunderstorms hit the southern portion of metro Denver. Heavy rainfall…as much as 2.89 inches in 38 minutes…caused widespread street flooding in southeast Denver. Two feet of water covered a section of I-25. Hail up to golf ball size accompanied the storm in Littleton and Englewood…along with 60 mph winds.
In 1984…a heavy thunderstorm drenched Littleton with up to 2.35 inches of rain in an hour…along with small hail that piled up to 2 inches deep. Flood waters were up to 4 feet deep in parts of town with many basements flooded. There were some power outages caused by lightning.
In 1990…a thunderstorm dumped 1.25 inches of rain in 12 minutes near tower and smoky hill roads in southeast Aurora. Minor street flooding was reported in the area.
In 1992…a pilot reported two funnel clouds near Cheery Creek Reservoir. Both dissipated quickly. Dime size hail fell near Franktown.
In 1994…one inch diameter hail fell near Strasburg. No damage was reported.
In 1999…a dog kennel east of Denver International Airport… Was flooded when a small dam…upstream in Elbert County… Was breached. The floodwaters…up to 4 feet deep…washed away some 6-foot fences and other small buildings. Ten of the 70 dogs boarded at the kennel drowned.
In 2002…a mail carrier was struck by lightning as he inserted a key into a multi-unit mailbox in Bailey. The shock knocked the man back against the mail truck. He suffered minor injuries. Lightning struck a residence in Commerce City. The resulting fire destroyed the roof of a detached garage and damaged much of its contents. Hail as large as 1 3/4 inches in diameter pelted pine. One inch diameter hail fell in Arvada and southwest Denver. Heavy rain triggered a mudslide along U.S. Highway 285 near Bailey. Both lanes of traffic had to be closed until debris could be removed from the highway. Several residences in the Bailey and Glenisle areas were also flooded.
In 2004…heavy thunderstorm rainfall caused localized flash flooding in Virginia canyon near Idaho Springs. Sections of the Virginia Canyon Road had to be closed due to the floodwaters.
In 2008…a severe thunderstorm produced large hail…up to 1 1/4 inches in diameter…northeast of Parker. Several automobiles were damaged.
6
In 1877…a severe rain…hail…and wind storm struck Denver. The storm produced a one minute sustained wind speed of 75 mph. Rainfall totaled 1.00 inch in 25 minutes. The hail storm damaged vegetable gardens in the city.
In 1954…an unconfirmed tornado was reported in Westminster. A funnel cloud was sighted in the area…but it was not certain if it had touched down. No damage was reported.
In 1980…the temperature reached 100 degrees…setting a new record high for the date.
In 1982…3/4 inch diameter hail was reported in north Denver. Heavy rain caused street flooding in central Denver where 4 to 5 feet of water inundated I-25…closing the freeway for a while. Rainfall across metro Denver ranged up to 2.35 inches in just over an hour. An estimated 2000 basements were flooded. Only 0.01 inch of rain fell at Stapleton International Airport.
In 1991…heavy rain caused flooding at the junction of I-25 and I-70. Dime size hail was reported northeast of Boulder near Niwot.
In 1995…microburst winds gusting as high as 58 mph caused minor damage to an apartment complex in Broomfield. Some homes under construction were also damaged when the winds knocked over 2 by 4 wood beams along with some insulation and roofing materials…which broke a few windows. Microburst winds also overturned a camper near Barr Lake.
In 1996…hail ranging in size from 1 to 1 1/2 inches fell near Bennett.
In 2001…3/4 inch hail fell in the foothills near conifer.
In 2008…a record daily rainfall record was set at Denver International Airport. The record of 1.29 inches in 24 hours broke the previous record of 1.10 inches set in 1929.
7
In 1948…a brief west moving tornado was sighted 3 miles north-northeast of Stapleton Airport. The white funnel silhouetted against a gray cloud background was very narrow…nearly vertical…and estimated at nearly 5 thousand feet high. A dust cloud formed on the ground around the funnel. No damage was reported.
In 1952…a thunderstorm wind gust to 52 mph was recorded at Stapleton Airport.
In 2014…severe thunderstorms produced large hail across western and southern parts of metro Denver. Near Centennial and Golden…hail up to quarter size was reported. Near Bennett…a peak thunderstorm wind gust to 65 mph was also reported. At Denver International Airport…a peak wind gust to 46 mph was recorded.
8
In 1874…swarms of grasshoppers invaded the city. Millions of them were seen cruising through the air. The insects were apparently picked up by a thunderstorm gust front and carried into the city. The grasshoppers had ravaged crops in surrounding counties for the last month.
In 1878…the highest temperature ever recorded in Denver…105 degrees…occurred at 3:20 pm. This temperature was equaled on July 20th in 2005.
In 1969…the temperature reached 100 degrees at Stapleton International Airport.
In 1976…in Thornton…a 13 year old boy riding a bicycle was struck and killed by lightning.
In 2000…lightning struck three homes in central Arapahoe County east of Denver. Damage was estimated at 47 thousand dollars.
In 2003…hail to 1 inch in diameter pelted Denver. Hail to 7/8 inch was measured in Boulder.
In 2008…heavy rain also caused flash flooding over south Denver and its nearby suburbs. Heavy rain…from 2.5 to 4 inches…fell in less than 90 minutes. Firefighters rescued 20 people as the water quickly rose along creeks…flooded roadways…and stranded motorists. Three people had to be rescued along Cherry Creek when the bike path flooded.
In Evergreen…a man suffered minor injuries when he was struck by lightning. It entered his finger…traveled down his body… And exited his foot.
In 2013…heavy rain caused localized flash flooding in Aurora. An undergound parking garage at an apartment complex was inundated with 3 to 4 feet of water. Flash flooding forced a road closure at East Mississippi Ave. and Alton St. Also… several people had to be rescued when three vehicles stalled in floodwaters at Alameda Ave. and Havana St. The stationary thunderstorms dumped 2.75 inches of rain in less than 45 minutes. In addition…large hail…up to one inch in diameter…was reported north of Roxbourough State Park. At Denver International Airport…just a trace of rainfall was observed.
Smoke from area wildfires helps color the sky orange at sunrise. (Jessica Fey)
Colorado offers outdoor opportunities unlike any other state and while the summer heat settles in, photos of the amazing scenes across our state provide a view into why we love it here so much.
The weather this time of year has a pretty standard pattern of quickly warming temperatures followed by afternoon thunderstorms that can cool things down. These storms sometimes provide a good bit of ‘excitement’ and are a prime photo subject.
Slideshow updated July 29, 2018
Recreationalists head outdoors and take advantage of urban, suburban and rural opportunities. As they do, our abundant wildlife that is found just about anywhere comes into focus.
Showcasing images captured by ThorntonWeather.com readers as well as some of our own, our monthly slideshow covers the entire gamut of weather and nature related imagery. Sunsets, sunrises, wildlife and of course every type of weather condition are vividly depicted.
To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.
[flickr_set id=”72157697199001551″]
What is missing in the slideshow above? Your photo!
Our monthly photo slideshow is going to feature images that we have taken but more importantly images that you have captured. The photos can be of anything even remotely weather-related.
Landscapes, current conditions, wildlife, pets, kids. Whimsical, newsy, artsy. Taken at the zoo, some other area attraction, a local park, a national park or your backyard. You name it, we want to see and share it!
Images can be taken in Thornton, Denver or anywhere across the extraordinary Centennial State. We’ll even take some from out of state if we can tie it to Colorado somehow.
We’ll keep the criteria very open to interpretation with just about any image eligible to be shown in our slideshows.
What do you win for having your image in our slideshow? We are just a ‘mom and pop’ outfit and make no money from our site so we really don’t have the means to provide prizes. However you will have our undying gratitude and the satisfaction that your images are shared on the most popular website in Thornton.
To share you images with us and get them included in the slideshow just email them to us or share them with ThorntonWeather.com on any of the various social media outlets. Links are provided below.
Time for a break! We’ll be largely incommunicado for a few days while getting some much-needed R & R. The good thing is that the weather looks to be relatively calm while we are gone. As always, keep an eye on our website for all the latest including real-time conditions, forecasts, and much more.
July 29 to August 4: This week in Denver weather history
The effects of our annual monsoon season are portrayed in detail in our look back at this week in Denver weather history. Numerous cases of flooding resulting from heavy rainfall are seen as are other severe weather events including hail and even tornadoes.
From the National Weather Service:
13-5
In 2008…a streak of 24 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874. Ironically…no new single day record high temperatures were set in the month of July. In August however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on August 2nd.
18-2
In 1987…a streak of 16 consecutive days of 90 degrees ranked 4th on the list of hot streaks. The record of 24 consecutive days was established in the summer of 2008.
27-31 in 1956…96 percent of the total precipitation for the month of July occurred over the last five days of the month. Heavy thunderstorms produced 4.00 inches of rainfall at Stapleton Airport. This amount of precipitation in 5 days or less had been exceeded only 3 times in previous record. The last time had been in December of 1913 as snow. Considerable property damage occurred across metro Denver from flooding.
28-30
In 1889…dense smoke from forest fires in the mountains obscured the sun over the city for three days.
In 1971…a vigorous cold front late on the 28th produced northeast wind gusts to 39 mph and record breaking cold temperatures on the 29th and 30th. The temperature dipped to 47 degrees on the 29th and 43 degrees on the 30th… Setting record minimums for the dates. Upslope cloudiness along with rain and fog early on the 29th helped set a record low maximum temperature of 58 degrees for the date.
29
In 1878…a total eclipse of the sun was observed at 2:20 pm. From before to during the eclipse…the temperature in the sun fell from 114 degrees to 82 degrees…while the shade temperature fell from 89 degrees to 83 degrees.
In 1880…heavy thunderstorm rain and hail flooded streets and ditches.
In 25 minutes…0.76 inch of rain fell on the city along with large hail to 3/4 inch in diameter. There were no strong winds with the storm.
In 1890…a thunderstorm produced sustained west winds to 48 mph with gusts to 60 mph…but only 0.01 inch of rain.
In 1956…heavy rain and hail fell over west and north Denver.
In 1964…hail to 3/4 inch in diameter fell at Lowry Airfield.
In 1978…a small tornado was sighted just east of Parker. No damage was reported.
In 1989…heavy rain drenched all areas of the Front Range… Both in the foothills and adjacent plains. Amounts of 1 to 3 inches were general over the area. Damage was confined to a few minor road washouts and some street…basement…and crop flooding. Thunderstorm rainfall totaled 1.44 inches at Stapleton International Airport where north winds gusted to 43 mph. Lightning struck a 250 thousand dollar home near Nederland and started a fire which destroyed all of it except two garages. Lightning started a fire in a home in Evergreen. It reached the house by hitting a tree…then traveling through a metal clothesline strung between the tree and the building.
In 1995…thunderstorm winds gusted to 59 mph in Brighton. Thunderstorm winds from the south-southeast gusted to 41 mph at Denver International Airport. High temperature of 99 degrees was a new record maximum for the date in Denver.
In 1997…heavy rain caused flooding in an apartment building in Westminster. Several residents had to be evacuated from their apartments. A woman in aspen park received minor injuries…when lightning passed through an office window and struck her. She suffered temporary blindness for about 15 minutes.
In 2003…hail as large as 1 inch in diameter pelted Conifer… Highlands Ranch…and Franktown.
29-30
In 1997…heavy rain caused flooding and flash flooding in central portions of Adams and Arapahoe counties. Two homes were extensively damaged when water flooded the basements and adjacent pasture area in Strasburg. Water 4 to 5 feet deep had pooled in the lower lying areas of the town. A portion of Quincy Road was closed in Arapahoe County when 4 feet of water covered the roadway. Rainfall totaled 3.06 inches at Denver International Airport…establishing a new record for 24-hour rainfall in July. The previous record was 2.42 inches set in 1965 on the 24th and 25th.
30
In 1879…lightning struck a brick kiln in north Denver. Three men were knocked senseless…but all recovered. Rainfall in the city was only 0.09 inch.
In 1881…a thunderstorm dumped heavy rain and hail on the city…causing street flooding and much damage. A heavy torrent of rain fell with 1.10 inches measured in just 20 minutes. Storm total rainfall was 1.60 inches. The rain turned streets into running streams. Wood street crossings were torn up and washed away. The storm caused great damage by flooding many cellars where goods were stored. The brick yards suffered severe damage when the heavy rainfall destroyed many unfired bricks.
In 1913…northeast winds were sustained to 41 mph with gusts to 48 mph.
In 1939…a thunderstorm produced 0.08 inch of rainfall. This was the only measurable precipitation of the month…making the month the second driest July on record.
In 1961…heavy rain and lightning disrupted power lines and caused flooding in Denver. Thunderstorm rains totaled 1.60 inches at 11th and Lincoln in central Denver.
In 1972…the temperature climbed to a high of 100 degrees at Stapleton International Airport.
In 1983…hail 3/4 to 1 inch in diameter fell in central and southeast Denver and in Littleton. Rainfall of 1.50 inches occurred in just 30 minutes in Littleton. There was some street flooding in both cities with wind gusts up to 55 mph.
In 1984…central Aurora was hit by a downpour that produced 1.80 inches of rain and sent water 2 to 3 feet deep into some streets. Before the rain stopped later in the evening… The storm had dropped as much as 2.80 inches of moisture on the city. Thunderstorm rainfall totaled only 0.82 inch at Stapleton International Airport.
In 1985…a tornado was spotted in open country 10 miles southwest of Bennett. No damage was reported. One inch hail was reported in south Lakewood.
In 1997…one man was killed and his girlfriend critically injured when they were struck by lightning on the Kennedy Golf Course in southeast Denver. Both were struck in the head when they took refuge under a tree during a downpour. Lightning struck a home in unincorporated Arapahoe County east of Buckley Field. The fire started in the electrical panel boxes…causing extensive damage to the home. Heavy rain and hail triggered a flash flood in Boulder…which sent water through a window of the financial aid office on the University of Colorado campus. In addition…ceiling tiles…carpets…and dressing rooms were damaged at the Coors Events Center when a pipe draining rainwater broke during the downpour. In all…10 buildings on the campus received water damage estimated at 100 thousand dollars. Hail as large as 1.25 inches in diameter accompanied the heavy rain in Boulder. Thunderstorm rainfall totaled 2.71 inches at Denver International Airport where west winds gusted to 41 mph. This was the greatest calendar day official precipitation ever recorded in July.
In 1998…heavy rain…up to 3 inches in an hour…caused flash flooding problems from Castle Rock to Parker. I-25 north of Castle Rock was closed as high waters covered sections of the highway. Some cars were left floating in the flood waters.
In 2001…a severe thunderstorm produced a wind gust to 70 mph at a wind sensor on the northeast corner of Denver International Airport.
In 2004…a severe thunderstorm produced wind gusts to 71 mph in Evergreen.
In 2005…the temperature climbed to a high of 101 degrees at Denver International Airport. This was a new record maximum temperature for the date.
In addition…this was the 7th day of the month with a high temperature of 100 degrees or more…which set a new Denver record for the most 100 degree days in a month…for a season…and in a year.
31
In 1873…the all-time lowest recorded temperature in July… 42 degrees…occurred. The same temperature also occurred on July 4…1903.
In 1874…during the late afternoon rain and hail fell for 5 minutes followed by brief heavy rain. Pieces of solid ice of irregular shape fell upon the roof of the station. The hail stones measured 1 1/2 inches in diameter. Precipitation (rain and melted hail) was only 0.16 inch.
In 1889…the high temperature climbed to 100 degrees in downtown Denver.
In 1919…heavy thunderstorm rainfall totaled 2.59 inches in downtown Denver during the evening. Rainfall was 1.90 inches in an hour…a new record at that time.
In 1961…over an inch of rain in a short period of time caused flooding of streets and basements in Denver. Rainfall totaled 1.30 inches at 11th and Lincoln in central Denver.
In 1964…the temperature reached 91 degrees in Denver…making this the 27th day of the month that the temperature reached 90 degrees or more. This is the all time record for 90 degree days in a month in Denver.
In 1972…one inch diameter hail fell in Hudson northeast of Denver.
In 1976…during the evening hours extremely heavy thunderstorm rains produced flash flooding in Big Thompson Canyon which killed 144 people between Estes Park and Loveland. No significant weather occurred in metro Denver at the time.
In 1987…1 inch diameter hail fell in Lakewood and 3/4 inch hail fell near Louisville. Southeast Boulder County was drenched with 1.25 inches of rain in just 20 minutes.
In 1993…thunderstorm winds damaged a chimney of a home near Parker.
In 1996…a weak tornado (f0) was sighted 12 miles east of Denver International Airport. No damage was reported.
In 1998…heavy monsoonal thunderstorm rain triggered a mud slide in Blackhawk. The mudslide blocked Main St. and caused an estimated half million dollars in damage to a casino. Heavy thunderstorm rain…up to 3 inches in an hour…caused a flash flood along Buffalo Creek. Portions of County road 126 just south of the town of Buffalo Creek were washed out. The flood waters nearly washed away the bridge as mud and debris slammed into the structure. Hail to 1 3/4 inches in diameter fell near Idaho Springs.
In 2004…severe thunderstorm winds toppled a 65-foot blue spruce tree in Parker. The tree landed on a home damaging the roof and gutters. The downed tree poked dozens of holes into the shingles.
In 2013…severe thunderstorm winds…with gusts estimated to 80 mph…downed power poles which caused scattered outages in and around Byers…Bennett and Strasburg. Some property damage was also observed. Near Byers…aluminum siding and roofing was peeled off sheds. Large hail…up to one inch in diameter…was reported north of Bennett. At Denver International Airport… a peak wind gust to 40 mph was observed from the northeast.
July 22 to July 28: This week in Denver weather history
As we near the end of July the weather in Denver tends to be a bit more stable. That doesn’t mean the severe weather threat disappears as can be seen at our look back at this week in Denver weather history. Particularly notable are lightning injuries and deaths, flash flood events and even tornadoes.
From the National Weather Service:
7-25
In 1934…a streak of 15 consecutive days of 90 degrees ranked 5th on the list of hot streaks. The record of 24 consecutive days was established in the summer of 2008.
13-5
In 2008…a streak of 24 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874. Ironically…no new single day record high temperatures were set in the month of July. In August however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on August 2nd.
18-2
In 1987…a streak of 16 consecutive days of 90 degrees ranked 4th on the list of hot streaks. The record of 24 consecutive days was established in the summer of 2008.
19-23
In 2005…the high temperature climbed above 100 degrees on each of the 5 days with readings of 101 on the 19th…105 on the 20th…104 on the 21st…and 102 on both the 22nd and 23rd. A new record maximum temperature for the month of July of 105 degrees was set on the 20th…which also equaled the all time record maximum for Denver of 105 degrees first set on August 8th in 1878. Daily maximum temperature records were set on each day…and the 5 day period equaled the record for the most consecutive days of 100 degrees or more first set from July 4th through 8th in 1989. The intense heat resulted in a high use of electricity for cooling purposes. The demand for electric power exceeded the supply and rolling black-outs… Each lasting about an hour…were scheduled across metro Denver during the afternoons and early evenings.
20-23
In 1961…unusually cool weather for July resulted in several temperature records. Record minimum temperatures were set or equaled on each day with readings of 51…51…49… And 49 degrees. High temperature of only 64 degrees on the 21st was a record low maximum for the date.
20-25
In 1965…heavy showers and thunderstorms doused metro Denver with significant rain each day. Rainfall for the six days totaled 5.16 inches at Stapleton International Airport. Massive rainfall occurred on the 20th…21st…and 25th… Flooding streets and basements and causing streams to overflow. The heaviest rainfall…2.05 inches…at Stapleton International Airport occurred on the 25th.
22
In 1874…a severe thunderstorm during the late afternoon produced 1.36 inches of rainfall in an hour…most of which fell in 20 minutes. There was much damage from flooding of streets and considerable damage to private property. The lightning was brilliant and continuous during the storm. Seven buildings were struck by lightning in the city…in addition to many places where it struck only the ground. A magnificent example of ball lightning was observed. When about 200 feet above the house tops…the ball exploded and broke into 7 or 8 different balls…each about 6 inches in diameter. Upon reaching about 20 feet above the ground…these balls broke into small fragments about 3 inches long and 1/2 inch wide. A shed situated in an alley about one block away was literally covered with these sparks. After the storm was over…the shed and adjacent area showed no trace of the event. Not the slightest mark could be detected on structures or on the ground.
In 1879…a terrific electrical storm passed over the city during the afternoon. The lightning display was unusually vivid and the crash of thunder seemed at the very house tops. A few homes and buildings were struck by lightning. A home on Capitol Hill sustained much damage to furniture… But the residents in another wing of the house were not injured. Lightning struck a fence at the corner of Curtis and Broadway. A lightning bolt stunned a workman and knocked a mason’s trough from his hand. A school was struck but was not damaged. Lightning struck the ground near tenth and Colfax. Rain fell in torrents for a time…but the heaviest was on the outskirts of the city. Rainfall in the city was only 0.30 inch.
In 1882…lightning struck and killed a man in the northern part of the city.
In 1895…heavy rainfall of 1.53 inches was measured in downtown Denver.
In 1931…the high temperature reached 100 degrees in downtown Denver.
In 1965…lightning struck and killed a boy standing by an automobile near Stapleton International Airport. Scattered heavy showers accompanied by hail and wind occurred across metro Denver. Heavy rain caused some street damage in Commerce City.
In 1973…minor thunderstorm wind damage was reported in Aurora.
In 1983…heavy thunderstorms dumped torrential rain and large hail across metro Denver. The most serious problems were caused by heavy rainfall in the foothills…which produced flooding on bear creek. Runoff from 3 inches of rain in 45 minutes at Kittredge caused bear creek to rise 5 feet in 10 minutes at Morrison…washing out two bridges. One bridge collapsed…plunging a fire truck into the water…but the occupants were not injured. The town was evacuated for 2 hours. Evergreen was drenched with 2.61 inches of rain in 30 minutes…which caused street flooding along with power outages. Hail to golf ball size damaged cars. A deck on a house east of Evergreen was washed away. At Idaho Springs… 2 inches of rain fell in 45 minutes. Golden received 3 inches of rain in an hour with 0.80 inch of rain in seven minutes at Littleton. Heavy rain and large hail also fell in the city of Denver and its northern and eastern suburbs… Causing street flooding. Water was 6 feet deep on one Aurora street.
In 1991…heavy rains caused extensive flooding across north metro Denver. Ralston creek in Arvada flowed out of its banks. At the intersection of I-25 and I-70…up to 8 feet of water covered the highway. A foot of water covered a stretch of I-70 in northwest Denver. Thunderstorm rainfall totaled only 0.82 inch at Stapleton International Airport.
In 1998…lightning sparked a fire which caused extensive damage to a home in Englewood. Most of the second floor was destroyed.
In 2004…severe thunderstorms produced hail to 1.25 inches in diameter in Commerce City and near Brighton.
22-23
In 1991…heavy rains over the palmer divide and along the Front Range caused the South Platte River to flood from near Henderson to Fort Lupton. The river was out of its banks at several locations with water covering the roads through the night. Only minor damage was reported.
July 15 to July 21: This week in Denver weather history
Denver’s weather is rarely boring and our look back at this week in Denver weather history shows that. There have certainly been many notable thunderstorms with hail and damaging wind. However the most interesting item is the first – and only – recorded instance of snow during the month of July in the Mile High City.
From the National Weather Service:
7-25
In 1934…a streak of 15 consecutive days of 90 degrees ranked 5th on the list of hot streaks. The record of 24 consecutive days was established in the summer of 2008.
13-5
In 2008…a streak of 24 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874. Ironically…no new single day record high temperatures were set in the month of July. In August however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on August 2nd.
14-15
In 1985…thunderstorms dumped heavy rain and hail at numerous locations along the Front Range from Denver north. Some of the heaviest rain fell in northern and western suburbs of Denver. Up to 2.6 inches of rain drenched Arvada…and Thornton was soaked with 2 inches in 45 minutes. At least 5 homes in Arvada suffered extensive damage from water and mud…and many streets and basements were flooded. In southern Jefferson County…11 homes were struck by lightning.
15
In 1879…a terrific hail storm occurred in the vicinity of Buffalo Station on the south park railroad in the South Platte River canyon about 39 miles south of Denver. Stones as large as hen’s eggs fell thick and fast and broke nearly every pane of glass in the windows of the building. A “waterspout” or cloudburst caused much loss of property from flash flooding on a nearby gulch. The torrent of water caused a deafening roar as it uprooted trees and carried huge Boulders and other debris. It struck the house and sawmill simultaneously and carried them away like straws…leaving little behind. The water continued to rush down the gulch for several hours. Serious damage was done to the south park railroad. The track and roadbed were destroyed for several miles. At about the same time…heavy rains in the vicinity of the headwaters of Cherry Creek produced a rapid rise in the creek…which drowned a few head of cattle and washed away two footbridges and some fences. Only 0.10 inch of rainfall was recorded in Denver.
In 1896…a thunderstorm produced sustained southwest winds to 40 mph with gusts to 46 mph.
In 1902…the temperature reached a high of 100 degrees in downtown Denver…which was a record maximum for the date.
In 1929…a thunderstorm did considerable damage to property in the eastern portion of the city. Heavy hail ranging in size from 1/4 to 3/4 inch in diameter…severe lightning… And high winds accompanied the heavy rain. Basements were flooded…and streets were impassable in places for several hours due to the heavy rainfall. Lightning damaged several telephone poles. Hail did extensive damage to gardens and flowers. The hail was up to a foot deep in places. There was no estimate of damage from the storm. A thunderstorm produced only a trace of rain and east winds to 24 mph in downtown Denver.
In 1959…thunderstorm rain totaled 0.41 inch in 8 minutes and winds gusted to an estimated 50 mph near downtown Aurora where half inch diameter hail was also reported. After the storm moved to the east…complete double rainbows were observed from the weather bureau office at Stapleton Airport.
In 1962…hail pelted the area in Adams County around Henderson and Brighton…causing extensive damage to corn…grain…beets…and row crops. Crop damage was estimated at 250 thousand dollars.
In 1963…a man received severe burns when struck by lightning while painting a building in south Denver.
In 1965…a state patrolman sighted a tornado near Bennett. It touched down over open ground…but caused no damage.
In 1967…heavy rains flooded streets and underpasses in south Denver. Heavy rain and minor wind damage were reported in wheat ridge…Aurora…Englewood…and Littleton. Basements were flooded and power disrupted. The clouds and rain resulted in a high temperature of only 72 degrees…which was a record low maximum for the date.
In 1974…a severe lightning storm damaged several homes and caused a number of power outages in both Denver and western Arapahoe counties.
In 1975…lightning killed a girl west of Boulder.
In 1982…winds gusted to 60 mph at Stapleton International Airport…and strong winds blew down walls at a construction site in Aurora where a nearby tree was uprooted.
In 1985…0.79 inch of rain fell in 30 minutes at Castle Rock. Much of the town lost power when lightning struck the town’s transformer.
In 1992…a man was struck by lightning while horseback riding near Castle Rock. Two people were struck by lightning near Highlands Ranch in south metro Denver. A man was struck by lightning while riding in the back of a pick-up truck in Franktown. All received minor injuries. Strong thunderstorms moved through east metro Denver…producing large hail and flash flooding. Hail up to 1 1/4 inches in diameter fell near Buckley Air National Guard base. Rainfall of 1 to 3 inches fell in Aurora in less than an hour…leaving water up to 18 inches deep in some areas. Thunderstorm rainfall was measured at 0.97 inch at Stapleton International Airport…where 3/8th inch diameter hail fell and south winds gusted to 44 mph.
In 1993…dime size hail fell in Golden. National weather service observers at Stapleton International Airport sighted a small rope-like funnel overhead for about 3 minutes before it dissipated.
In 1994…a small…short-lived tornado caused damage to a house under construction in Parker.
In 1995…thunderstorm winds of unknown strength downed trees and branches…damaging a porch and nearby cars in Denver.
In 1998…hail to 7/8 inch in diameter fell near Keenesburg.
In 2000…this date marked the end of a near record hot streak for metro Denver. The high temperature at Denver International Airport equaled or exceeded the 90-degree mark for 17 consecutive days…from June 29th. This was one day short of equaling the all time record. The record of 18 consecutive days was set in two different years…July 1st-18th…1874 and July 6th-23rd…1901.
In 2005…severe thunderstorms produced large hail over southeast metro Denver. Hail as large as 1.75 inches in diameter fell in southwest Aurora along with 7/8 inch hail in centennial. Hail to 3/4 inch in diameter was measured near centennial airport and near Watkins.
In 2015…A severe thunderstorm produced a peak wind gust to 60 mph from the northwest at Denver International Airport. In addition…0.06 inches of rainfall was also observed.
In 2016…large hail ranging in size from 1 to 2 inches in diameter struck Aurora…Castle Rock…Centennial…Greenwood Village and southeast Denver. The hail shattered
15-16
In 2006…a brief mid July hot spell resulted in two 100 plus degree high temperatures and two daily maximum temperature records. The high temperature climbed to 101 degrees on the 15th and 103 degrees on the 16th at Denver International Airport.
16
In 1911…thunderstorm winds were sustained to 44 mph from the northwest.
In 1959…a thunderstorm produced 3/8 inch diameter hail and a wind gust to 60 mph at Stapleton Airport.
In 1972…two tornadoes were sighted by the public to the southeast of Aurora. No damage was reported.
In 1978…a thunderstorm wind gust to 52 mph was recorded at Stapleton International Airport.
In 1980…a severe thunderstorm ripped through metro Denver… Producing torrential rain…large hail…and strong winds.
In Aurora…winds gusted to 65 mph with hail up to 1 1/2 inches in diameter and half an inch of rain in just 10 minutes. Stapleton International Airport was closed for an hour. Large hail also fell in southeast Denver…Lakewood…Parker… And Castle Rock. Up to 1 1/2 inches of rain fell in just 40 minutes. Heavy rains in wheat ridge flooded a shopping center…breaking windows and doors…while causing 100 thousand dollars in damage. Some roofs and windows were damaged throughout metro Denver. At Stapleton International Airport where west winds gusted to 49 mph…1/4 inch hail and 0.77 inch of rain fell.
In 1983…severe thunderstorms dumped large hail over much of metro Denver. Hail to 3/4 inch in diameter fell in Littleton and Northglenn…with 3/4 to 1 inch hail in Arvada…1 to 1 1/2 inch hail in extreme northwest Denver…1 3/4 inch hail in Lakewood…1 1/2 inch hail in south Arvada and just northeast of Aurora…and 1 5/8 inch hail on green mountain.
In 1994…spotters reported a brief tornado touchdown in an open field just north of Fort Lupton. No damage or injuries were reported.
In 2000…very moist and unstable weather conditions…along with low level upslope flow during the late afternoon and evening…combined to produce heavy thunderstorm rainfall… Which caused urban and small stream flooding across metro Denver. Rainfall amounts generally ranged from 1 to 3 inches with the heaviest rainfall occurring during the evening hours. Two miles east of white ranch in northern Jefferson County… An automated rain gage measured 3.86 inches of rain. Since the rain fell in a relatively open area…no flood damage was reported. However…in greenwood village near the intersection of Peoria and Belleview…the streets were closed for several hours with as much as 2 feet of standing water covering the roadways. Two campers near Mt. Evans were injured by lightning and stranded overnight by the inclement weather. Both received minor injuries.
In 2003…the high temperature of 101 degrees was a record maximum temperature for the date.
In 2004…locally heavy rainfall of unknown amount caused parts of the Virginia Canyon road near Idaho Springs to wash out. The road had to be closed temporarily.
In 2005…the temperature climbed to a high of 102 degrees at Denver International Airport. This was a new record maximum temperature for the date at the time.
July 8 to July 14: This week in Denver weather history
In looking back at this week in Denver weather history, one cannot be struck by the hail storms listed, if not for sheer number then by the damage they caused. The biggest of these storms occurred in 1990 and stands in the books as the most damaging hailstorm in United States history.
From the National Weather Service:
29-15
In 2000…the 29th marked the beginning of a near record hot streak for metro Denver. The high temperatures…as recorded at Denver International Airport…exceeded the 90 degree mark for 17 consecutive days from June 29th through July 15th. The record of 24 consecutive 90 degree or above days was set from July 13th through August 5th…2008.
29-15
In 2000…the 29th marked the beginning of a near record hot streak for metro Denver. The high temperatures…as recorded at Denver International Airport…exceeded the 90 degree mark for 17 consecutive days from June 29th through July 15th. The record of 24 consecutive 90 degree or above days was set from July 13th through August 5th…2008.
1-18
In 1874…a streak of 18 consecutive days of 90 degrees tied for second with another streak that was later set in the summer of 1901. The record of 24 consecutive days was established in the summer of 2008.
4-8
In 1989…one of the most intense heat waves on record roasted metro Denver. The temperature reached 100 degrees or more on 5 consecutive days. The city had previously never recorded more than 2 straight 100-degree days since records began in 1872. Water and electricity usage reached all time highs. The heat wave created extremely dry weather conditions…which contributed to a major forest fire in Boulder canyon on July 9th. The temperature reached 103 degrees on the 8th…and the mercury climbed to 101 degrees on both the 4th and 5th…and to 102 degrees on both the 6th and 7th. The low temperature of 68 degrees on the 8th equaled the record high minimum for the date.
6-23
In 1901…a streak of 18 consecutive days of 90 degrees tied for second with another streak set in the summer of 1874. The record of 24 consecutive days was established in the summer of 2008.
7-25
In 1934…a streak of 15 consecutive days of 90 degrees ranked 5th on the list of hot streaks. The record of 24 consecutive days was established in the summer of 2008.
8
In 1905…a thunderstorm produced 0.82 inch of rainfall and northeast winds sustained to 48 mph.
In 1977…strong winds turned over 2 light aircraft at Arapahoe County Airport…now centennial airport.
In 1987…a weak tornado was observed near Bennett.
In 1988…three separate tornadoes were sighted near Bennett. No damage was reported. One inch diameter hail was also reported.
In 1991…lightning started three house fires in Castle Rock. Damage totaled 13 thousand dollars. No injuries were reported.
In 1993…a dry thunderstorm microburst wind gust to 55 mph briefly reduced the surface visibility to 3 miles at Stapleton International Airport.
In 1997…one construction worker was killed and two others injured when a strong thunderstorm wind gust caused the scaffolding they were standing on to collapse near Parker. A dry microburst produced a wind gust to 54 mph at Denver International Airport.
In 1998…heavy thunderstorm rain forced the closure of Hampden Avenue between I-25 and Havana Street in southeast Denver. The high water made 2 or 3 lanes of the street impassable.
In 2001…severe thunderstorms produced large hail…damaging winds…and heavy rain across south metro Denver. Two people received minor injuries when a severe thunderstorm wind gust to 58 mph blew over several tents at the Cherry Creek Arts Festival. The same storm caused the roof of a hardware store in Tamarac Square to collapse. One employee received minor injuries when she was struck in the head by falling debris. The combination of intense rain and wind downed trees and power lines. Electrical power outages affected 35 thousand homes and businesses. At least 50 trees in city parks across south Denver were damaged. Up to 4.50 inches of thunderstorm rain fell across portions of southeast metro Denver. The underpass at I-25 and Parker road was inundated with 5 feet of water. Several other streets and underpasses in Aurora were also closed due to high water. Heavy rain caused extensive damage to several exhibits at the Cherry Creek Arts Festival. Flash flooding occurred when heavy thunderstorm rainfall caused toll gate creek to jump its banks. Several underpasses across south Denver had to be closed due to high water. A man received minor injuries when lightning struck a nearby tree at the Wellshire Golf Course. Hail as large as 1 1/4 inches in diameter fell in Englewood with 1 inch hail in the city of Denver…and 3/4 inch hail in Littleton. Thunderstorm winds gusted to 63 mph at Denver International Airport and to 62 mph in Englewood.
In 2005…a tornado touched down briefly near Brighton…but caused no damage.
In 2011…severe thunderstorms produced hail…up to 1 inch in diameter…and wind gusts to 60 mph across parts of Adams…Broomfield and Denver counties. At Denver International Airport…a peak wind gust to 59 mph from the west.
In 2017…a strong thunderstorm produced hail up to 7/8 inch in diameter in southwest Denver.
9
In 1872…a very brisk wind between 2:00 pm and 3:00 pm spread a cloud of dust and sand into the city.
In 1874…northeast winds at sustained speeds up to 36 mph blew immense clouds of dust from the prairie through the streets of the city around mid-morning. The houses across the street from the weather station were not visible at the peak of the storm.
In 1875…heavy thunderstorm rains caused stream flooding… Which damaged nearly all railroads into the city. Rainfall in the city was only 0.14 inch.
In 1953…heavy thunderstorm rains caused an estimated 2 million dollars damage from flooded stores and basements across metro Denver. The flood waters reached a depth of 3 feet on streets in some sections of the city…damaging streets and automobiles. The heavy rainfall at Lowry Air Force Base totaled 3.90 inches. At Stapleton Airport where the heavy rain briefly reduced the surface visibility to 1/2 mile…only 1.05 inches of rain were measured. North winds gusting to 52 mph caused some damage in east Denver.
In 1982…two small tornadoes were spotted east of Rocky Flats… And a tornado touched down briefly 5 miles east of Brighton. No damage was reported.
In 1984…heavy rain fell over southern sections of metro Denver. Rainfall totaled 1.50 inches in just 15 minutes between Littleton and Sedalia.
In 1987…a thunderstorm microburst produced a wind gust of 58 mph at Erie north of Denver.
In 1988…hail to 3/4 inch in diameter piled up 2 to 4 inches deep in Idaho Springs. Some basements were flooded and several thousand gallons of fuel were contaminated when water flooded a gasoline storage tank. A tornado sighted near Manilla 5 miles west of Bennett remained on the ground for 9 minutes. No damage was reported.
In 1990…a severe thunderstorm produced a tornado and heavy rain over northeast metro Denver. As much as 4 inches of rain fell in just 20 minutes in Commerce City…causing the South Platte River to rise quickly and flood lowland areas. The raging flood waters caused extensive damage to a 30-foot stretch of railroad track embankment…destroyed a railroad trestle and a nearby garage…and washed away a vintage 1960’s show car near east 58th avenue and York Street. The car was found a couple of miles downstream in a pool of deep mud and murky water. Rainfall totaled 1.34 inches at Stapleton International Airport where 1/2 inch diameter hail fell. The same thunderstorm produced a brief tornado in a vacant field near 64th avenue and tower road just east of the rocky mountain arsenal. No damage was reported from the twister. Lightning from the storm caused power outages to as many as 7 thousand homes and businesses.
In 1996…a tornado (f0) was reported 5 miles south of Hudson. No damage was reported. Twin weak tornadoes (f0) formed for a short time near the northeast runways at Denver International Airport. Less than 15 minutes later…a weak tornado (f0) touched down in the employee parking lot at dia. Several car windows were blown out…and a few vehicles sustained minor body damage from flying debris. Several signs were also blown down. Later…twin weak tornadoes (f0) touched down again in open country between DIA and Watkins.
In 2004…severe thunderstorms produced hail to 3/4 inch in diameter near tiny town and wind gusts to 66 mph in Bennett. A thunderstorm wind gust to 56 mph was measured at Denver International Airport.
In 2005…a thunderstorm produced a wind gust to 54 mph at Denver International Airport.
9-10
In 1980…a series of severe thunderstorms hit metro Denver… Dumping heavy rain and producing a spectacular lightning display lasting for several hours. A number of homes were damaged by lightning. Winds gusted to 60 mph at Stapleton International Airport where about half an inch of rain fell in just 10 minutes along with 1/4 inch diameter hail. The evening thunderstorms continued into the early morning hours with total rainfall of 1.35 inches at Stapleton International Airport.
In 1998…thunderstorm rainfall totaled 2.04 inches at the site of the former Stapleton International Airport.
10
In 1878…a lunar rainbow was observed during a light mist and fog.
In 1895…the temperature warmed to a high of only 53 degrees… The all-time record lowest maximum temperature for the month of July.
In 1967…golf ball size hail damaged aircraft at Jefferson County Airport near Broomfield.
In 1983…two people were injured when struck by lightning just southwest of Morrison. A man was injured when he was swept downstream by a flash flood on a tributary of Clear Creek in the canyon 8 miles west of Golden. Heavy thunderstorm rains caused mudslides which closed several roads. Rainfall amounts included: 1.75 inches in 20 minutes in southeast Denver…1.26 inches in 35 minutes in Boulder…2.14 inches in 2 hours in Lakewood…1.70 inches in 45 minutes in Aurora…and 1.25 inches in 30 minutes atop Floyd Hill in the foothills west of Denver.
In 1992…storm spotters reported 3/4 inch diameter hail near the construction site of the new Denver airport just northeast of the city.
In 1995…microburst winds toppled a pine tree 60 feet high and 2 feet in diameter in Denver. The tree fell and injured a man nearby. Microburst winds to 59 mph broke the glass on a door at the national weather service forecast office at the site of the former Stapleton International Airport.
In 1998…thunderstorm rainfall totaled 2.35 inches at Denver International Airport.
In 2000…three children were injured…one critically…when lightning hit a nearby tree at panorama point atop flagstaff mountain just west of Boulder. Lightning hit the tree…entered the ground…then struck the children. Lightning sparked a grassfire that burned about 50 acres at the Rocky Flats Environmental Test Facility. Also… Lightning sparked at least 6 fires in the Hudson and Keenesburg areas as thunderstorms…accompanied with heavy rain…large hail…and tornadoes…moved through southern Weld County. Over 2 inches of very heavy rain caused flooding along an I-76 exit ramp near Keenesburg. The fire department rescued 15 stranded motorists as high water inundated sections of the exit ramp and adjacent highway. Basements were also flooded in Keenesburg. One home reportedly had 7 feet of standing water in the basement before the rain subsided. A weak tornado (f0) touched down briefly near Brighton…but caused no damage.
In 2001…a severe thunderstorm dumped 7/8 inch diameter hail in Wheat Ridge.
In 2002…severe thunderstorms pelted the southern suburbs of metro Denver with large hail. Hail as large as 3 inches in diameter fell 6 miles southeast of Parker. Other large hail reports included 2 inch diameter hail around centennial airport and 3/4 inch hail near Sedalia and Deckers. Hail as large as 3/4 inch was also reported in Broomfield. Runoff from heavy thunderstorm rainfall in the Hayman fire burn area flooded lost creek ranch with up to 18 inches of water just off State Highway 126. Floodwaters damaged a very expensive rug in the lodge. A driveway to a residence was washed away.
In Douglas County…runoff damaged forest access roads in the turkey creek drainage.
In 2011…a severe thunderstorm produced intense microburst winds in southeast Boulder County. A peak wind gust to 75 mph was recorded in superior with gust to 58 mph…2 miles south of Lafayette. At Denver International Airport…a peak wind gust of 31 mph was recorded.
The running theme so far for 2018 seems to be warmer than normal temperatures and drier that average conditions. That trend continued in June for Thornton.
Like May, June was somewhat a tale of two halves. The first half of the month was marked by very dry conditions with no precipitation until the 16th of the month. Similarly, overall temperatures trended well above normal during the first half of June.
While the warm and dry conditions were notable, the most memorable weather event came on the evening of the 18th when large hail pounded the northern half of Thornton. Extensive damage to homes and vehicles was seen as hailstones pushing 2 inches in diameter struck.
The month also featured Thornton’s hottest mercury reading in six years. We saw a high of 102.4 degrees on the 28th. You have to go back to June 25, 2012 to find a warmer reading (102.9). Additionally, the reading ties for the second warmest high temperature ThorntonWeather.com has recorded since coming online in 2007.
Thornton saw an overall average temperature for the month of 71.3 degrees. This was well above the 30 year average June temperature for Denver of 67.4 degrees. Out at DIA where Denver’s official measurements are taken, it was even warmer with an average for the month of 72.4 degrees.
Temperatures ranged from a high of 102.4 degrees on the 28th down to a low of 46.8 degrees on the morning of the 25th. The Mile High City saw it warmest reading of 105 on the 28th as well and its coldest reading of 44 degrees on the 2nd.
The National Weather Service reports that June 2018 will go into the books as the seventh warmest June on record for Denver. Additionally, three days saw record tying or setting highs. The 5th brought a record high of 95 degrees, the 6th saw a record-tying high of 95 degrees and the 105 degree reading on the 28th was a record for that date.
Denver averages 1.98 inches of precipitation during the month of June. Both Thornton and Denver fell short of that mark. Thornton saw 1.28 inches fall in its rain bucket while at the airport, it was even drier with only 0.43 inches.
June 2018 temperature summary chart for Thornton, Colorado. (ThorntonWeather.com)June 2018 precipitation summary chart for Thornton, Colorado. (ThorntonWeather.com)
CLIMATE REPORT
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
320 PM MDT SUN JUL 1 2018
...................................
...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF JUNE 2018...
CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2018
WEATHER OBSERVED NORMAL DEPART LAST YEAR`S
VALUE DATE(S) VALUE FROM VALUE DATE(S)
NORMAL
................................................................
TEMPERATURE (F)
RECORD
HIGH 105 06/28/2018
06/26/2012
06/25/2012
LOW 30 06/02/1951
HIGHEST 105R 06/28 104 1 99 06/20
LOWEST 44 06/02 30 14 42 06/13
AVG. MAXIMUM 88.8 82.4 6.4 85.5
AVG. MINIMUM 56.0 52.3 3.7 53.6
MEAN 72.4 67.4 5.0 69.5
DAYS MAX >= 90 16 7.9 8.1 9
DAYS MAX <= 32 0 0.0 0.0 0
DAYS MIN <= 32 0 0.0 0.0 0
DAYS MIN <= 0 0 0.0 0.0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 4.96 1882
MINIMUM T 1890
TOTALS 0.43 1.98 -1.55 0.33
DAILY AVG. 0.01 0.07 -0.06 0.01
DAYS >= .01 5 8.4 -3.4 5
DAYS >= .10 2 4.6 -2.6 2
DAYS >= .50 0 1.4 -1.4 0
DAYS >= 1.00 0 0.3 -0.3 0
GREATEST
24 HR. TOTAL 0.25 06/17 TO 06/17
SNOWFALL (INCHES)
TOTAL 0.0 0.0
RECORD 0.4 1919
DEGREE_DAYS
HEATING TOTAL 9 62 -53 25
SINCE 7/1 5410 6058 -648 5109
COOLING TOTAL 241 133 108 167
SINCE 1/1 289 155 134 173
FREEZE DATES
RECORD
EARLIEST 09/08/1962
LATEST 06/08/2007
EARLIEST 10/07
LATEST 05/05
.................................................................
WIND (MPH)
AVERAGE WIND SPEED 10.5
RESULTANT WIND SPEED/DIRECTION 1/129
HIGHEST WIND SPEED/DIRECTION 40/240 DATE 06/05
HIGHEST GUST SPEED/DIRECTION 57/160 DATE 06/27
SKY COVER
AVERAGE SKY COVER 0.40
NUMBER OF DAYS FAIR 11
NUMBER OF DAYS PC 16
NUMBER OF DAYS CLOUDY 3
AVERAGE RH (PERCENT) 42
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORMS 12 MIXED PRECIP 0
HEAVY RAIN 2 RAIN 5
LIGHT RAIN 5 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 0
HEAVY SNOW 0 SNOW 0
LIGHT SNOW 0 FOG W/VIS <=1/4 MILE 1
FOG 5 HAZE 2
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
July 1 to July 7: This week in Denver weather history
In our July weather preview we discussed how the month is not only Denver’s hottest but also its stormiest. Our look back at this week in Denver weather history helps to illustrate that fact. We start seeing 100+ degree days as well as many of the types of fast moving thunderstorm events expected this time of year.
From the National Weather Service:
29-2
In 1990…almost a year to date after the record breaking heat in early July 1989…the third longest heat wave in Denver history started. From June 29th through July 2nd the temperature reached 100 degrees or more on four consecutive days. The highest reading of 102 degrees occurred on the 29th…30th…and 1st. Combined with the 102 degree reading on June 27th this would have been the longest heat wave on record…but the temperature climbed to only 98 degrees on June 28th.
29-15
In 2000…the 29th marked the beginning of a near record hot streak for metro Denver. The high temperatures…as recorded at Denver International Airport…exceeded the 90 degree mark for 17 consecutive days from June 29th through July 15th. The record of 24 consecutive 90 degree or above days was set from July 13th through August 5th…2008.
30-1
In 1873…heavy rainfall overnight totaled 1.42 inches. Mountain peaks to the southwest of the city were covered with fresh snow on the morning of the 1st.
1
In 1915…northeast winds sustained to 41 mph with gusts to 50 mph occurred just before a thundershower in the evening. Rainfall was only 0.07 inch.
In 1941…unusually heavy thunderstorm rains flooded basements and blocked traffic. Water was curb high on many downtown streets. The thunderstorm also pelted the city with hail of unknown size. Rainfall in downtown Denver totaled 0.72 inch…but greater amounts likely occurred in other parts of the city.
In 1960…a severe dust devil moving through an Adams County suburban area blew over a fireworks stand…injuring an 11- year-old boy customer and two women operators of the stand. The boy was found under the demolished stand 100 feet away.
In 1961…hail as large as 1 1/4 inches in diameter was reported over east Denver.
In 1967…golf ball size hail fell over portions of metro Denver. Hail stones to 2 inches in diameter damaged roofs and broke windows in northeast Boulder. Marble to golf ball size hail fell at the Boulder airport. A funnel cloud was sighted over the foothills near Boulder. Hail stones of 1 to 2 inches in diameter were measured at Jefferson County Airport near Broomfield. Marble size hail fell in the vicinity of Arvada and Westminster.
In 1982…severe thunderstorms dropped large hail in Denver… Boulder…Commerce City…Lakewood…Wheat Ridge…Golden…and Arvada. Most locations reported hail size from 3/4 to 1 1/4 inches in diameter.
In 1990…the high temperature reached 102 degrees at Stapleton International Airport.
In 1998…hail to 1 1/2 inches in diameter fell near Bennett.
In 2001…the temperature climbed to a high of 101 degrees at Denver International Airport.
In 2016…a severe thunderstorm produced large hail in Castle Rock…ranging in size from 1 to 2 inches in diameter. The hail pummeled neighborhoods as it smashed cars and shattered windows. The storm caused extensive damage to shutters…roofs…siding and fencing.
1-18
In 1874…a streak of 18 consecutive days of 90 degrees tied for second with another streak that was later set in the summer of 1901. The record of 24 consecutive days was established in the summer of 2008.
1-31
In 2012…it was the hottest July on record in Denver since weather records began in 1872. The average temperature for the month was 78.9 degrees which was 4.7 degrees above normal. There were 27 days in which the high temperature equaled or exceeded 90 degrees…which established a new record. There were also 7 days in which the temperature equaled or exceeded 100 degrees which tied the record set in 2005.
2
In 1879…a severe hail storm produced considerable damage in the vicinity of Arvada. Some of the stones were unusually large…measuring 6.5 inches in circumference (2 inches in diameter) with an average weight of 1 ounce. The stones were uniformly large with one side concave. The greatest damage was to early wheat…cabbage…and vines. A tree just to the south of the weather station in downtown Denver was struck by lightning. Residents in the house 15 feet away were affected by the strike.
In 1885…thunderstorm winds were sustained to 50 mph in the city.
In 1892…an apparent cold front produced sustained northeast winds to 40 mph with gusts to 45 mph.
In 1955…a apparent microburst wind gust to 69 mph was recorded at Stapleton Airport where the brief strong wind reduced the visibility to zero in blowing dust.
In 1965…hail…up to 2 inches in diameter…struck southwest Adams and northeast Denver counties…damaging cars…windows… And foliage. Hail accumulated up to a foot deep. Wind gusts to 48 mph and hail to 1 inch in diameter fell at Stapleton International Airport where the large hail broke three storm windows and shredded shrubs at the U.S. Weather Bureau Upper Air building.
In 1968…a pilot reported a tornado 10 miles southeast of Parker.
In 1971…one inch diameter hail stones were reported in Adams County about 30 miles east of Denver.
In 1987…a large tornado touched down 10 miles northeast of Stapleton International Airport. The tornado was vertical and thick and kicked up a large dust and debris cloud. Later…it developed a sinuous rope-like shape as it slowly dissipated. The tornado was visible for 15 minutes. The twister occurred in open country and did only minor damage to a metal shed…porch…and mailbox. A man was killed by lightning in southwest Aurora. He was in his backyard and had a shovel in his hand at the time of the strike. A group of soccer players were hit by lightning on a field in Boulder. A 10-year-old boy was critically injured and hospitalized; fortunately he recovered. Six other people were knocked to the ground by the strike. Two of these were slightly injured. Golf ball size hail fell just east of Littleton and at Highlands Ranch. Hail as large as 3/4 inch in diameter was reported in Aurora and Parker and near Hudson and Franktown.
In 1988…a 45-year-old man was injured by lightning at Cheery Creek Reservoir. Administration of CPR probably saved his life.
In 1990…the temperature reached a high of 100 degrees at Stapleton International Airport.
In 1993…thunderstorm winds blew a roof off a barn near Parker…causing an estimated 15 hundred dollars damage.
In 1994…thunderstorm winds downed power lines in Boulder… Causing power outages. Winds gusted to 66 mph in Boulder… 64 mph in Arvada…and 60 mph in Golden.
In 1998…a small tornado touched down briefly near Barr Lake… But caused no damage.
In 2002…hail as large as 1 3/4 inches in diameter fell in the city of Denver and in Arapahoe County near Littleton. The low temperature of 69 degrees equaled the record high minimum for the date.
In 2006…lightning struck a teenager in Castle Rock as he was mowing his lawn and listening to an iPod. The teen suffered burns to his hands and feet…and had blood running from his ears when he was found. The victim’s eardrums were ruptured…which damaged his hearing. Lightning also struck a house in Castle Rock causing extensive damage to the roof and side of the home. Heavy rains caused flash flooding at Castlewood Canyon State Park near Franktown. The floodwaters destroyed four footbridges along the high trail. A culvert and several roads were washed out in the area. In addition… Two driveways crossing Cherry Creek were washed out near Prairie Canyon Ranch. Heavy rainfall also caused minor flooding on murphy and sand creeks…just east of Buckley AFB. Gun Club Road was closed between Alameda and Mississippi avenues…north of the Murphy Creek Golf Course…where 3 feet of standing water reportedly covered the road. A severe thunderstorm produced large hail to 7/8 inch in diameter in south Aurora near Cherry Creek.
In 2016…a weak landspout touched down briefly in and open field near Bennett.
