Many years in Colorado are marked by significant weather events. The Christmas Blizzards of 2006, the severe thunderstorms that dominated June of 2009 or reaching even further back the Thornton Tornado of 1981. The same can’t entirely be said about 2010 as we experienced a relatively quiet year without any truly major events.
Temperatures
In terms of temperatures the year was slightly warmer than the historical average of 50.1 degrees. In 2010 Denver officially recorded an annual average of 51.2 degrees at Denver International Airport. Thornton was actually spot on Denver’s historical average at 50.1 degrees.
Denver temperatures ranged from a high of 102 degrees on July 17th down to -16 on January 7th. The July high was a record for the date but the January low didn’t fall far enough to set a record. Thornton’s high temperature for the year was 101.6 degrees and our low was -9.7 degrees – both occurring on the same dates as Denver’s.
The average high temperature for the year was 65.3 degrees – 1.1 degrees above normal. The average low was 37.0 degrees, 1.2 degrees above normal. Thornton’s average highs and lows were very close to Denver’s at 65.7 degrees and 36.8 degrees respectively.
DIA reported 47 days with temperatures at or above 90 degrees – 16 above normal. Thornton stayed cooler recording only 38 days. Low temperatures dipped below freezing on 158 days in Denver (2 above normal) while Thornton had one more with 159 days.
Snowfall
The first half of the 2010 to 2011 snowfall season was dismal as Denver recorded a mere 4.8 inches and Thornton recorded 4.9 inches. This is the second lowest total on record for the period with the only year with less snow being 1888 when 3.8 inches was recorded.
Through the end of December only two days with measureable snowfall were seen with most of it falling right at the end of the year on December 30th and 31st. For comparison the snowiest half-season was in 1913 when 72.8 inches was recorded!
Reaching back to January and looking at the entire calendar year snowfall was poor over the period as well. The year finished with only 27.8 inches recorded at DIA. Thornton fared quite a bit better with 37.68 inches.
Precipitation
Denver averages 15.81 inches of precipitation per year. In 2010 we fell well short of that mark having recorded 12.86 inches – 2.95 below normal. Like with the snowfall, Thornton did much better than DIA on the precipitation front recorded 15.09 inches.
While dry, the year was not one of the top 10 driest on record. The 10th driest occurred in 1901 when 9.10 inches was recorded and the wettest was in 1967 when 23.31 inches of precipitation fell into the bucket.
July 2010 was the wettest month of year with 3.7 inches of precipitation measured at DIA. The month just barely missed making the top 10 wettest Julys by 0.01 inch. Highlighting the vast differences that occur over a relatively small distance, Thornton recorded 1.35 inch in July. Our wettest month was actually June with 3.1 inches.
Two months later September brought the driest month of the year when only 0.06 inch of precipitation was recorded tying it for the 5th driest September on record. January was similarly dry when only 0.07 inch of precipitation was recorded tying the mark for the 6th driest January. In the dry months Thornton matched closely to Denver with 0.09 recorded in September and 0.06 in January.
Records for the year
Denver set or tied 14 records during 2010. Nine record highs were set or tied, 3 high minimum temperatures were set or tied, one 24 hour precipitation record was set and 2 maximum wind gust records were set.
Severe weather
There was really very little drama in the Denver metro area in terms of severe weather in 2010. There were a few damaging hail events, including one in Thornton in June, but they were not particularly extraordinary.
For Colorado as a whole 66 tornadoes were reported during the year. For comparison, 58 were reported in 2009, 39 in 2008 and 53 in 2007. Since 1950 Colorado has averaged around 30 tornadoes per year. The most ever recorded was 98 in 1996.
Arguably one of the most picturesque tornadoes of the year in the entire nation occurred on Memorial Day near Campo, Colorado. The long-lived tornado tore across open ranchland for more than 20 minutes. Click here for more details.
Climate summary for 2010
Following is the official climate summary for 2010 from the National Weather Service for Denver. Click here to view the Thornton 2010 climate report.
...THE DENVER CO CLIMATE SUMMARY FOR THE YEAR OF 2010...
CLIMATE NORMAL PERIOD 1971 TO 2000
CLIMATE RECORD PERIOD 1872 TO 2010
WEATHER OBSERVED NORMAL DEPART LAST YEAR`S
VALUE DATE(S) VALUE FROM VALUE DATE(S)
NORMAL
................................................................
TEMPERATURE (F)
RECORD
HIGH 105 07/20/2005
08/08/1878
LOW -29 01/09/1875
HIGHEST 102 07/17 64 38 98 08/23
LOWEST -16 01/07 36 -52 -17 12/09
AVG. MAXIMUM 65.3 64.2 1.1 63.5
AVG. MINIMUM 37.0 35.8 1.2 36.0
MEAN 51.2 50.1 1.1 49.7
DAYS MAX >= 90 49 33.1 15.9 18
DAYS MAX <= 32 13 22.2 -9.2 26
DAYS MIN <= 32 158 156.1 1.9 161
DAYS MIN <= 0 5 9.0 -4.0 7
PRECIPITATION (INCHES)
RECORD
MAXIMUM 23.31 1967
MINIMUM 7.48 2002
TOTALS 12.86 15.81 -2.95 18.12
DAILY AVG. 0.03 0.04 -0.01 0.05
DAYS >= .01 71 89.1 -18.1 94
DAYS >= .10 24 MM MM 45
DAYS >= .50 9 MM MM 12
DAYS >= 1.00 3 MM MM 3
GREATEST
24 HR. TOTAL 1.84 07/04 TO 07/04
SNOWFALL (INCHES)
RECORDS
TOTAL 118.7 1908-09
24 HR TOTAL 23.6 12/24/1982
SNOW DEPTH MM MM
TOTALS 27.8 MM MM 63.7
LIQUID EQUIV 2.78 MM MM 6.37
SINCE 7/1 4.8 MM MM 37.6
LIQUID 7/1 0.48 MM MM 3.76
SNOWDEPTH AVG. LESS THAN 0.1 MM MM 0
DAYS >= TRACE 42 (SINCE 01/01) MM MM 49
DAYS >= 1.0 10 (SINCE 01/01) MM MM 19
GREATEST
SNOW DEPTH 8 03/24 7 03/27
24 HR TOTAL 10.8 03/23 TO 3/24 8.3 03/26 TO 3/27
DEGREE_DAYS
HEATING TOTAL 5774 6128 -354 5994
SINCE 7/1 2072 2486 -414 2739
COOLING TOTAL 870 696 174 533
SINCE 1/1 870 696 174 533
FREEZE DATES
RECORD
EARLIEST 09/08/1962
LATEST 06/08/2007
EARLIEST 10/07
LATEST 05/05
.................................................................
WIND (MPH)
AVERAGE WIND SPEED 9.6
RESULTANT WIND SPEED/DIRECTION 2/195
HIGHEST WIND SPEED/DIRECTION 52/220 DATE 05/24
HIGHEST GUST SPEED/DIRECTION 64/220 DATE 05/24
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
NUMBER OF DAYS FAIR 91
NUMBER OF DAYS PC 219
NUMBER OF DAYS CLOUDY 55
AVERAGE RH (PERCENT) 52
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 48 MIXED PRECIP 0
HEAVY RAIN 10 RAIN 21
LIGHT RAIN 63 FREEZING RAIN 0
LT FREEZING RAIN 2 HAIL 5
HEAVY SNOW 4 SNOW 13
LIGHT SNOW 47 SLEET 1
FOG 97 FOG W/VIS <= 1/4 MILE 38
HAZE 61
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.