Category Archives: Climatology

December 2013 weather recap: Record setting hot and cold, little snow

Thornton and the Denver area closed out 2013 with a display of typically highly variable weather.  We recorded some record low temperatures followed by unseasonably warm conditions.  One thing that was lacking was snow.

The first three days of the month started out quite mild with highs well above normal.  That changed quickly midday on the third as low pressure moved in bringing an extended Arctic blast.

For six straight days high temperatures remained stubbornly below freezing and lows dipped into the single digits.  The cold snap was notable but not record-setting in terms of length.  Two daily low temperature records were tied or broken however.

Warmer weather returned on the 10th as the mercury finally started to climb.  Unseasonably warm temperatures became the rule for the next nine days that included a record high temperature on the 18th.

The last third of the month was a bit more variable with its ups and downs but overall warmer than normal conditions.

Overall Thornton’s monthly average temperature came in at 29.2 degrees.  Out at Denver International Airport where the Mile High City’s official stats are recorded, it was a bit cooler with an average of 28.4 degrees.  Both were below Denver’s December average of 30.0 degrees.

Thornton recorded nine days with high temperatures that failed to reach 32 degrees.  On five days, low temperatures dropped below zero.  Denver saw eight days with highs below freezing, six with lows below zero.

The warmest temperature of the month in Thornton came on the 18th when we recorded 66.8 degrees. Our coldest was -9.3 degrees on the 5th.  Denver’s warmest day was on the 18th as well with a high of 68 degrees.  Its lowest temperature was -15 degrees on the 5th.

Four temperature records were tied or broken in Denver.

The low temperature of -13 degrees on December 4th shattered the old record low for the date of -5 degrees last set in 2008.  The following day, on December 5th, the low temperature of -15 degrees tied the record low last set in 1972.

The mild weather December 18 saw two records.  The high of 68 degrees broke the previous high temperature record for the date of 66 degrees last set in 1979.  Also, the day tied the record high minimum for the 18th of 40 degrees set in 1917.

Precipitation for the month of December 2013 was not as noteworthy as the temperatures.  Thornton recorded only 0.24 inches in our bucket while Denver received 0.25 inches.  Both were a good bit below the December average of 0.35 inches.

Snow was similarly less than extraordinary.  Thornton measured 5.7 inches of the white stuff while Denver lagged that with 4.7 inches.  Both totals were below the normal for December of 8.5 inches.  Seasonal snowfall totals at this point are about half of what they normally are.

Click here to view Thornton’s December 2013 climate summary.

Thornton's December 2013 Temperatures.
Thornton’s December 2013 Temperatures.
Thornton's December 2013 Precipitation.
Thornton’s December 2013 Precipitation.
CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
200 AM MST WED JAN 1 2014

...................................

...THE DENVER CO CLIMATE SUMMARY FOR THE YEAR OF 2013...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2013

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH             105   06/26/2012
                        06/25/2012
                        07/20/2005
 LOW              -29   01/09/1875
HIGHEST           100   07/11        64      36      105  06/26
                        06/11                             06/25
LOWEST            -15   12/05        36     -51       -6  01/11
AVG. MAXIMUM     63.9              64.7    -0.8     68.4
AVG. MINIMUM     36.3              36.3     0.0     39.3
MEAN             50.1              50.5    -0.4     53.9
DAYS MAX >= 90     54              39.6    14.4       73
DAYS MAX <= 32     29              20.0     9.0       19
DAYS MIN <= 32    169             156.9    12.1      132
DAYS MIN <= 0      11               5.8     5.2        4 
PRECIPITATION (INCHES) 
RECORD 
 MAXIMUM        23.31   1196 
 MINIMUM         7.29   2008 
TOTALS          17.60             14.30    3.30    10.11 
DAILY AVG.       0.05              0.04    0.01     0.03 
DAYS >= .01        82              79.7     2.3       52
DAYS >= .10        42              34.9     7.1       23
DAYS >= .50         8               7.6     0.4        9
DAYS >= 1.00        3               2.3     0.7        1
GREATEST
 24 HR. TOTAL    2.39   MM                       12/31 TO 12/31
                                                          12/31 TO 12/31
                                                          12/31 TO 12/31
 STORM TOTAL       MM                                 MM
 (MM/DD(HH))            MM                    12/31(00) TO 12/31(00)
                                                 12/31(00) TO 12/31(00)1
                                                 12/31(00) TO 12/31(00)1

SNOWFALL (INCHES)
RECORDS
 TOTAL             MM   5
 24 HR TOTAL       MM
 SNOW DEPTH        MM   MM
TOTALS           74.1              53.8    20.3     38.5
 LIQUID EQUIV    7.41              5.40    2.01     3.85
SINCE 7/1         8.1              22.5   -14.4     12.4
 LIQUID 7/1      0.81              2.20   -1.39     1.24
SNOWDEPTH AVG.      0                MM      MM        0
DAYS >= TRACE      60              33.3    26.7       36
DAYS >= 1.0        20              16.3     3.7       13
GREATEST
 SNOW DEPTH         9   02/25                         11  02/04
 24 HR TOTAL      9.1   MM                       12/31 TO 12/31
                                                          12/31 TO 12/31
                                                          12/31 TO 12/31
 STORM TOTAL       MM                                 MM
 (MM/DD(HH))            MM                    12/31(00) TO 12/31(00)
                                                 12/31(00) TO 12/31(00)1
                                                 12/31(00) TO 12/31(00)1

DEGREE_DAYS
HEATING TOTAL    6302              6059     243     5198
 SINCE 7/1         MM              2468      MM       MM
COOLING TOTAL     999                 0     999     1236
 SINCE 1/1        999               769     230     1236

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
..................................................

WIND (MPH)
AVERAGE WIND SPEED              9.7
RESULTANT WIND SPEED/DIRECTION   2/201
HIGHEST WIND SPEED/DIRECTION    64/060    DATE  06/18
HIGHEST GUST SPEED/DIRECTION    97/040    DATE  06/18

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR           69
NUMBER OF DAYS PC            232
NUMBER OF DAYS CLOUDY         64

AVERAGE RH (PERCENT)     52

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN               14     RAIN                      25
LIGHT RAIN               80     FREEZING RAIN              0
LT FREEZING RAIN          4     HAIL                       0
HEAVY SNOW               11     SNOW                      23
LIGHT SNOW               58     SLEET                      0
FOG                     105     FOG W/VIS <= 1/4 MILE     33
HAZE                     88

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

Thornton’s December preview: A very chilly month quite possible

November was an unseasonably warm and unusually dry month. As we look into December, that trend looks to change, particularly when it comes to temperatures.

The month brings with it the official start to winter and the month usually brings with it our first real taste of Arctic temperatures. Precipitation can be hit or miss with monster snowstorms possible but we have also seen starkly dry years.

Current long range forecasts indicate that for at least the first half of the month we will see unusually cold temperatures and have the potential for better than average levels of precipitation.

Get all the details on Thornton’s December weather including a look back at historical events and a look at the long range forecast in our December weather preview here.

October 2013 weather recap: Cooler than normal temperatures, first snow recorded

Thornton and Denver’s October 2013 was overall a relatively un-noteworthy month in terms of weather.  Temperatures were below normal and we did receive our first measurable snowfall of the season.

We started the first two days of the month with temperatures in the 70s.  That was followed by a cold front moving through and delivering 0.8” of snow in Thornton on the 4th while Denver recorded only a trace at DIA.

We then saw five days of dry conditions with temperatures warming back up into the 70s.  On the 10th the next system arrived and rain was recorded on four of the next five days in Thornton.  Cooler than normal temperatures were notable during the period and lasted for the next eight days.

On the 18th another shot winter-like weather arrived and Thornton saw its biggest snowfall yet of the season: 2.4 inches.  Out at the airport, Denver recorded 1.4 inches.

The next nine days from the 19th to the 27th were largely pleasant days but with light rain on two days during that time.  On the 28th another cold front and storm system moved in and chilly temperatures returned.  Thornton recorded a dusting of snow on the 30th.

Overall temperatures for the month averaged 47.7 degrees as measured officially at DIA.  Here in Thornton our average temperature was slightly cooler at 45.9 degrees.  Both marks were considerably cooler than the historical October average temperature of 50.9 degrees.

Temperatures in Thornton ranged from a high of 79.5 degrees on the 8th down to a low of 25.5 degrees on the 16th.  Denver’s high and low were similar with 79 degrees also on the 8th and 27 degrees on the 5th and 16th.

One temperature record was set in Denver during the month.  On October 5 the low temperature reading of 28 degrees tied the record low for the date last set in 1877.

In terms of precipitation, Thornton recorded 1.21 inches between rainfall and snowmelt.  Denver was drier recording only 0.72 inches.  The Mile High City historically averages 1.02 inches so Thornton was above average, Denver below.

With only small snowfalls recorded, it wasn’t a particularly white month.  Thornton measured a total of 3.3 inches while Denver recorded only 1.4 inches.  Both were below the October average of 4.0 inches.

Click here to view Thornton’s October 2013 climate summary report.

[pe2-image src=”http://lh4.ggpht.com/-D-mSqpy-pQc/UnQi63nQ0FI/AAAAAAAAA3Q/_8y6TRKhmuE/s144-c-o/October2013Temps.jpg” href=”https://picasaweb.google.com/108306177534978229224/Misc?authkey=Gv1sRgCNPjmpm5l5PSOA#5941412203164913746″ caption=”Thornton’s October 2013 Temperatures.” type=”image” alt=”October2013Temps.jpg” pe2_single_image_size=”w560″ pe2_img_align=”left” ]

[pe2-image src=”http://lh5.ggpht.com/-d6PD6Dq3lto/UnQi_K0Q-dI/AAAAAAAAA3Y/L7pCMZAzn7E/s144-c-o/October2013Precip.jpg” href=”https://picasaweb.google.com/108306177534978229224/Misc?authkey=Gv1sRgCNPjmpm5l5PSOA#5941412277039200722″ caption=”Thornton’s October 2013 Precipitation.” type=”image” alt=”October2013Precip.jpg” pe2_single_image_size=”w560″ pe2_img_align=”left” ]

CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
240 AM MDT FRI NOV 1 2013

...................................

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF OCTOBER 2013...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2013

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              90   10/01/1892
 LOW               -2   10/29/1917
HIGHEST            79   10/08        90     -11       83  10/03
LOWEST             27   10/16        -2      29       24  10/27
                        10/05
AVG. MAXIMUM     60.0              65.3    -5.3     62.2
AVG. MINIMUM     35.5              36.6    -1.1     35.9
MEAN             47.7              50.9    -3.2     49.0
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      0               0.4    -0.4        1
DAYS MIN <= 32     12               8.5     3.5       11
DAYS MIN <= 0       0               0.0     0.0        0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         4.17   1969
 MINIMUM            T   1934
TOTALS           0.72              1.02   -0.30     1.22
DAILY AVG.       0.02              0.03   -0.01     0.04
DAYS >= .01         8               5.3     2.7        5
DAYS >= .10         3               2.4     0.6        3
DAYS >= .50         0               0.5    -0.5        2
DAYS >= 1.00        0               0.1    -0.1        0
GREATEST
 24 HR. TOTAL    0.25   10/18 TO 10/18           10/24 TO 10/25
                        10/03 TO 10/04                    10/25 TO 10/25
                                                          10/25 TO 10/25
 STORM TOTAL       MM                                 MM
 (MM/DD(HH))            MM                    10/25(00) TO 10/25(00)
                                                 10/25(00) TO 10/25(00)5
                                                 10/25(00) TO 10/25(00)5

SNOWFALL (INCHES)
RECORDS
 TOTAL             MM   MM
TOTALS            1.4               4.0

DEGREE_DAYS
HEATING TOTAL     525               440      85      488
 SINCE 7/1        608               581      27      557
COOLING TOTAL       0                 5      -5        1
 SINCE 1/1        999               769     230     1236

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST      10/04             10/07
LATEST                          05/05
......................................................

WIND (MPH)
AVERAGE WIND SPEED              8.8
RESULTANT WIND SPEED/DIRECTION   1/180
HIGHEST WIND SPEED/DIRECTION    40/270    DATE  10/10
HIGHEST GUST SPEED/DIRECTION    48/270    DATE  10/10

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.50
NUMBER OF DAYS FAIR           12
NUMBER OF DAYS PC             14
NUMBER OF DAYS CLOUDY          5

AVERAGE RH (PERCENT)     61

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       3
LIGHT RAIN                9     FREEZING RAIN              0
LT FREEZING RAIN          1     HAIL                       0
HEAVY SNOW                1     SNOW                       2
LIGHT SNOW                4     SLEET                      0
FOG                      13     FOG W/VIS <= 1/4 MILE      9
HAZE                      4

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

August 2013 weather recap: Thornton sees average temps, dry conditions

Looking back at last month we certainly do recall the unseasonably warm temperatures that seemed to dominate August 2013.  While the high temperatures were indeed high, somehow Thornton managed to end up with a relatively average temperature and precipitation short of normal.

The month started with temperatures into the 90s and much-needed precipitation on two of the first three days.  Thunderstorms on the third provided a bit of excitement including strong winds and some hail.

From there the month turned a good bit cooler with seasonal temperatures on many days and even two days (the 7th and 8th) when highs were in the 70s.  The latter half of the month however saw a return of the heat with 13 of the final 16 days of the month registering high temperatures at or above 90 degrees.

Looking at the statistics one can easily see how different weather conditions can be across a relatively small area.  While Thornton saw a monthly average temperature near normal, Denver was considerably warm.  Similarly, our precipitation was below the Denver long term average but out at the airport it was well above average.

In terms of temperatures, the August average temperature in Thornton was 72.0 degrees.  This was right near the 1981 to 2010 Denver average for the month of 72.5 degrees.  Out at DIA however, the average temperature was a considerably higher 74.6 degrees.

Thornton’s highest temperature of the month was 97.6 degrees on the 20th.  Our lowest was 50.2 degrees on the 15th.  Officially, Denver’s highest temperature recorded was 99 degrees on the 20th and its lowest 52 degrees on that same day.

Three temperature records were broken in Denver during August 2013.

A new record high of 97 degrees was recorded on August 17 (96 degrees, 1994).  On August 20 a record high of 99 degrees was recorded as well (98 degrees, 1987).  Also on the 20th, a record high minimum of 70 degrees was set (67 degrees, 2007).

Denver’s long term precipitation for the month of August is 1.69 inches.  Thornton fell short of that mark as we registered 1.37 inches in our rain bucket.  More than an inch of that was the result of thunderstorms on two days (the 3rd and the 21st).

Denver was able to best us by a large margin recording 2.78 inches of precipitation in August 2013.  The bulk of the Mile High City’s precipitation fell on the 22nd when they registered 1.94 inches from a slow moving thunderstorm, one which missed Thornton entirely.

One precipitation record was set in Denver during August 2013.  The 1.94 inches of rainfall on the 22nd was a record for the date, easily besting the old record of 0.75 inches set in 1953.

Click here to view Thornton’s August 2013 climate summary.

Thornton, Colorado August 2013 Temperatures.
Thornton, Colorado August 2013 Temperatures.
Thornton, Colorado August 2013 Precipitation.
Thornton, Colorado August 2013 Precipitation.
...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF AUGUST 2013...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2013

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH             105   08/08/1878
 LOW               40   08/26/1910
                        08/25/1910
                        08/24/1910
HIGHEST            99   08/20       105      -6       98  08/27
                                                          08/03
                                                          08/06
LOWEST             52   08/09        40      12       47  08/17
AVG. MAXIMUM     89.4              87.2     2.2     91.0
AVG. MINIMUM     59.8              57.9     1.9     58.9
MEAN             74.6              72.5     2.1     75.0
DAYS MAX >= 90     16              11.5     4.5       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         5.85   1979
 MINIMUM         0.02   1924
TOTALS           2.78              1.69    1.09     0.11
DAILY AVG.       0.09              0.05    0.04     0.00
DAYS >= .01         7               8.6    -1.6        1
DAYS >= .10         2               4.3    -2.3        1
DAYS >= .50         2               1.2     0.8        0
DAYS >= 1.00        1               0.3     0.7        0
GREATEST
 24 HR. TOTAL    1.95   08/21 TO 08/22           08/11 TO 08/11
                                                          08/10 TO 08/11
                                                          08/11 TO 08/11
 STORM TOTAL       MM                                 MM
 (MM/DD(HH))            MM                    08/11(00) TO 08/11(00)
                                                 08/11(00) TO 08/11(00)1
                                                 08/11(00) TO 08/11(00)1

SNOWFALL (INCHES)
RECORDS
 TOTAL             MM   MM
TOTALS            0.0               0.0

DEGREE_DAYS
HEATING TOTAL       0                10     -10        0
 SINCE 7/1          0                16     -16        0
COOLING TOTAL     308               244      64      319
 SINCE 1/1        866               688     178     1122

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
..................................................

WIND (MPH)
AVERAGE WIND SPEED              8.8
RESULTANT WIND SPEED/DIRECTION   3/204
HIGHEST WIND SPEED/DIRECTION    43/110    DATE  08/03
HIGHEST GUST SPEED/DIRECTION    55/060    DATE  08/03

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR            4
NUMBER OF DAYS PC             23
NUMBER OF DAYS CLOUDY          4

AVERAGE RH (PERCENT)     48

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                2     RAIN                       3
LIGHT RAIN               11     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                0     SNOW                       0
LIGHT SNOW                0     SLEET                      0
FOG                       4     FOG W/VIS <= 1/4 MILE      2
HAZE                     10

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

July 2013 State of the Climate: U.S. warmer, wetter than average

Significant Climate Events - July 2013 (NOAA)
Significant Climate Events – July 2013 (NOAA). Click for larger view.

The National Oceanic and Atmospheric Administration (NOAA) released its July 2013 State of the Climate report saying that while the average U.S. temperature was warmer than normal, precipitation was higher than normal.

As we reported earlier, here in the Denver area temperatures were largely average during the month.  Precipitation was close to normal but fell short of that mark.

The SOTC’s larger view shows the contiguous United States’ average temperature was 0.8° above the 20th century average.  This ranks it as the 30th warmest July on record.

In terms of precipitation, the nation enjoyed a wetter than average month, one that ranks it as the 5th wettest July since record-keeping began.

Below are the climate highlights from NOAA for July 2013.  Click here to view the full, comprehensive report.

From NOAA:

Climate Highlights — July

  • The average temperature for the contiguous U.S. during July was 74.3°F, 0.8°F above the 20th century average, and ranked as the 30th warmest such month on record.
  • The western U.S. was warmer than average, where IdahoNevadaOregon, and Utah each had a top ten warm month. Several cities, including Salt Lake City, Utah, and Reno, Nev., had their warmest July on record.Seven states across the Northeast also had July temperatures ranking among the ten warmest on record, including Massachusetts and Rhode Island, each of which had a record warm July.
  • Locations from the Central and Southern Plains into the Southeast were cooler than average. Four states —AlabamaArkansasMississippi, and Tennessee — had July temperatures that were among the ten coolest on record.
  • The Alaska statewide average temperature was 1.7°F above the 1971-2000 average and ranked as the fifth warmest July on record for the state. Anchorage had its fourth warmest July, and the city set a record with 14 consecutive days above 70°F.
  • The nationally-averaged July precipitation total of 3.47 inches was 0.71 inch above average and was the 5thwettest July on record for the contiguous United States.
  • Wetter-than-average conditions stretched from California, through the Southwest and Plains, and along the Eastern Seaboard. In the Southwest, seasonal monsoonal flow brought above average precipitation to several states, where Arizona and California both had July precipitation totals ranking among their ten wettest. During this time of year in parts of the Southwest, even light precipitation can result in above-average monthly totals but have minimal impacts on alleviating drought conditions.
  • In the East13 states had one of their ten wettest Julys on record, with the highest precipitation totals across the Southeast. Florida had its wettest July on record, with 12.38 inches of rainfall, 4.91 inches above average. The above-average precipitation in the Southeast resulted in widespread flooding and significant damage to crops.
  • The Northwest was particularly dry. Oregon had its driest July on record with only 0.03 inch of rainfall accumulating, 0.41 inch below average. Washington had its eighth driest July. Below-average precipitationwas also observed in the Upper Mississippi River Valley, where Iowa had its tenth driest July.
  • According to the July 30 U.S. Drought Monitor report, 45.6 percent of the contiguous U.S experienced drought conditions, up slightly from the beginning of July. Drought remained entrenched throughout much of the West and in parts of the Central and Southern Plains, and drought expanded into parts of the Lower Mississippi River Valley and Midwest. Over 20 percent of Alaska was in drought at the end of July, with severe drought developing in central parts of the state.
  • Based on NOAA’s Residential Energy Demand Temperature Index (REDTI), the contiguous U.S. temperature-related energy demand during July was above average and ranked as the 41st highest July value in the 119-year period of record.
  • The components of the U.S. Climate Extremes Index (USCEI) that examine extremes in warm night time temperatures, the spatial extent of wetness and drought, and extremes in days with rainfall were all above average. When combined with the other components of the index, the USCEI, as a whole, was only slightly above average. The USCEI is an index that tracks the highest and lowest 10 percent of extremes in temperature, precipitation, tropical cyclones, and drought across the contiguous United States.
  • On a local basis, the number of record warm daily highs and lows (2560) during July was roughly the same as the number of record cool daily highs and lows (2846), although there were slightly more cool records.
  • Climate Highlights — year-to-date (January – July)
  • The year-to-date contiguous U.S. temperature of 51.8°F was 0.5°F above the 20th century average and tied with 1952 as the 42nd warmest January–July on record. Above-average temperatures were observed in the West and Northeast, where CaliforniaNew Hampshire, and Vermont had one of their top ten warmest year-to-date periods. Below-average temperatures stretched from the Northern Plains to the Southeast.
  • The year-to-date contiguous U.S. precipitation total of 19.14 inches was 1.54 inches above average and tied with 1997 as the 22nd wettest January–July on record. However, rainfall was not evenly distributed across the country. Dry precipitation extremes were observed in the West and wet precipitation extremes were observed in the East.
  • CaliforniaIdahoNevada, and Oregon each had a top ten dry year-to-date period. California’s precipitation total of 4.58 inches was record low for the seven-month period at 9.82 inches below average, and 1.69 inches less than the previous record dry January–July of 1898.
  • Above-average precipitation was observed across most locations east of the Rockies, with ten states having one of their ten wettest year-to-date periods. Michigan was record wet with 24.35 inches of precipitation, 6.92 inches above average, and 2.30 inches above the previous record wet January–July of 1950. Several cities, from Fargo, North Dakota to Greenville, South Carolina, had a record wet January–July.
  • Based on NOAA’s Residential Energy Demand Temperature Index (REDTI), the contiguous U.S. temperature-related energy demand during January–July was below average and ranked as the 47th lowest January–July value in the 119-year period of record.
  • The components of the USCEI that examine extremes in the spatial extent of drought, as well as 1-day precipitation totals and days with rainfall were much above average for the year-to-date. When combined with the other components of the index, the USCEI, as a whole, was only slightly above average.

Regional Highlights for the Colorado area

High Plains Region: (Information provided by the High Plains Regional Climate Center)

  • Average temperatures were generally below normal in the east and above normal in the west across the High Plains Region this month. Temperature departures of 2.0-4.0 degrees F (1.1-2.2 degrees C) below normal occurred in eastern Kansas, central South Dakota, western North Dakota, and a few pockets of Nebraska. Meanwhile, western portions of Colorado and Wyoming had temperature departures of 3.0-5.0 degrees F (1.7-2.8 degrees C) above normal. The cooler temperatures in the east were in stark contrast to last year, when a good portion of the area had temperature departures of 6.0-8.0 degrees F (3.3-4.4 degrees C) above normal. Although monthly records were not set, a few stations did manage to sneak in to the top 10 rankings for warmest or coolest July. On the cool side, long-term station Wamego 4 W, which is located in northeastern Kansas, had its 5th coolest July with an average temperature of 75.6 degrees F (24.2 degrees C). The coolest July at Wamego 4 W was 72.0 degrees F (22.2 degrees C) in 1950 (period of record 1912-2013). On the warm side, Lander, Wyoming had its 10th warmest July with 74.2 degrees F (23.4 degrees C). Interestingly, 7 of the top 10 warmest Julys have occurred since 2000 in Lander and the top spot of 75.9 degrees F (24.4 degrees C) occurred in both 2003 and 2006 (period of record 1891-2013). While monthly extremes were not common, numerous daily records occurred throughout the month. One notable record was for the July all-time coolest maximum temperature in Concordia, Kansas. On July 28th, Concordia’s high temperature only reached 62.0 degrees F (16.7 degrees C) and beat out the old record of 63.0 degrees F (17.2 degrees C) which occurred back in 1979 and 1988 (period of record 1885-2013).
  • July precipitation was hit or miss across the High Plains Region. Areas receiving at least 150 percent of normal precipitation included central Kansas, central South Dakota, central and western Colorado, and scattered pockets in eastern Wyoming, north central Nebraska, southwestern South Dakota, and northern North Dakota. While rain was needed to help alleviate ongoing drought conditions, some storms brought heavy rain which caused mudslides in fire burn scars in Colorado and flash flooding in parts of Colorado, Kansas, and Wyoming. Areas which missed out included eastern and central Nebraska, eastern and central North Dakota, and central Wyoming. These areas received less than 50 percent of normal precipitation. Because of the wide range in precipitation, there were stations which ranked in the top 10 driest or wettest Julys on record. With only 11 percent of normal precipitation, Omaha, Nebraska had its 2nd driest July on record with 0.44 inches (11 mm) of precipitation (period of record 1871-2013). The driest on record occurred only last year with 0.01 inches (0 mm). Meanwhile, precipitation in central Kansas helped alleviate drought conditions there, although long-term deficits were still high. For instance, Wichita, Kansas had measurable precipitation on 17 days in July, which broke the old record of 16 in 1950 (period of record 1888-2013). On average, Wichita has about 8 days with measurable precipitation in July. By the end of the month, Wichita received 7.69 inches (195 mm) of precipitation making this July its 4th wettest. Although 232 percent of normal, this was not nearly enough to beat the top spot of 13.37 inches (340 mm) in 1950.
  • The latest U.S. Drought Monitor showed both improvements and degradations over the past month. At the end of July, approximately 64 percent of the Region was in moderate (D1) to exceptional (D4) drought – down just slightly from 67 percent at the end of June. An expansion of abnormally dry conditions (D0) occurred in east-central North Dakota and eastern parts of Kansas, Nebraska, and South Dakota. In addition, two new areas of D1 were introduced in far southeastern South Dakota and northeastern Kansas. One category improvements were made in some areas of north-central and eastern Colorado. There was quite a bit of jostling of drought conditions in Kansas where some areas had improvements, while others had degradations. By the end of the month, 25 percent of the state remained in the D4 designation, however. Wyoming had an increase in severe (D2) and extreme (D3) drought coverage, going from about 47 percent of the state to 52 percent of the state. According to the U.S. Seasonal Drought Outlook released July 18th, the only area of drought expected to improve was in southwestern Colorado. Drought conditions were expected to develop in north-central Colorado and persist elsewhere through October 2013.
  • For more information, please go to the High Plains Regional Climate Center Home Page.

July 2013 weather recap: Mostly normal conditions prevail

Following two hot and dry months in May and June, July brought some relief in the form of near normal temperatures and precipitation.

Cooler than normal temperatures started the month during the first couple of days of July.  That changed for the following 10 days when temperatures bounced to above normal levels with Thornton recording eight 90+ degree days during the period.

The next few days from the 14th to the 16th brought much cooler conditions and much-needed precipitation.  Seasonal temperatures then settled in through the 23rd.  As the month came to a close, temperatures became more moderate and we even saw three days (the 27th, 28th, and 29th) with highs in the 70s.  Most notably we once again saw some precipitation.

Thornton saw an average temperature during July of 72.1 degrees.  This was a good bit below the long term Denver historical average of 74.3 degrees.  Officially at DIA the average temperature for the month was 74.2 degrees.

We recorded 14 days with temperatures at or equal to 90 degrees.  Temperatures ranged from a high of 98.5 degrees on the 11th down to a low of 52.6 degrees on the 27th.

A reasonable 1.61 inches of precipitation fell into Thornton’s rain bucket during the month.  This was a bit below the average for July of 2.16 inches.  Out at the airport, Denver fared a bit better with 1.98 inches.

Click here to view Thornton’s July 2013 climate summary.

Thornton, Colorado July 2013 Temperatures.
Thornton, Colorado July 2013 Temperatures.
Thornton, Colorado July 2013 Precipitation.
Thornton, Colorado July 2013 Precipitation.
CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
210 AM MDT THU AUG 1 2013

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF JULY 2013... 

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2013

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           100   07/11       105      -5      102  07/21
LOWEST             55   07/02        42      13       57  07/26
AVG. MAXIMUM     88.2              89.4    -1.2     94.4
AVG. MINIMUM     60.4              58.9     1.5     63.4
MEAN             74.3              74.2     0.1     78.9
DAYS MAX >= 90     17              16.0     1.0       27
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           1.98              2.16   -0.18     0.48
DAILY AVG.       0.06              0.07   -0.01     0.02
DAYS >= .01         7               8.3    -1.3        6
DAYS >= .10         4               4.3    -0.3        2
DAYS >= .50         2               1.4     0.6        0
DAYS >= 1.00        0               0.7    -0.7        0
GREATEST
 24 HR. TOTAL    0.87   07/15 TO 07/15           07/06 TO 07/07
                        07/14 TO 07/15                    07/31 TO 07/31
                        07/15 TO 07/15                    07/31 TO 07/31
 STORM TOTAL       MM                                 MM
 (MM/DD(HH))            MM                    07/07(00) TO 07/07(00)
                                                 07/31(00) TO 07/31(00)1
                                                 07/31(00) TO 07/31(00)1

SNOWFALL (INCHES)
RECORDS
 TOTAL             MM   MM
TOTALS            0.0               0.0

DEGREE_DAYS
HEATING TOTAL       0                 6      -6        0
 SINCE 7/1          0                 6      -6        0
COOLING TOTAL     295               289       6      438
 SINCE 1/1        558               444     114      803

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
.................................................. 

WIND (MPH)
AVERAGE WIND SPEED              10.3
RESULTANT WIND SPEED/DIRECTION   3/163
HIGHEST WIND SPEED/DIRECTION    45/050    DATE  07/20
HIGHEST GUST SPEED/DIRECTION    58/040    DATE  07/20

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR            5
NUMBER OF DAYS PC             24
NUMBER OF DAYS CLOUDY          2

AVERAGE RH (PERCENT)     50

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                2     RAIN                       3
LIGHT RAIN               13     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                0     SNOW                       0
LIGHT SNOW                0     SLEET                      0
FOG                       6     FOG W/VIS <= 1/4 MILE      1
HAZE                     13

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

Denver breaks low temperature record for date, ties all time May low temperature

Record Cold Temperatures
Denver’s recent cold continued as this morning one low temperature record was broken, another tied.

In the wake of our May Day snowstorm, clear skies the following morning allowed temperatures to plummet and reach very winter-like levels.  As the mercury bottomed out, Denver broke one low temperature record and tied another.

As measured at Denver International Airport, the temperature this morning dropped to 19 degrees at 6:41am.  This easily breaks the previous record low temperature for May 2 of 22 degrees  set in 1954.

Most notably, the 19 degree reading also tied the record for the lowest temperature ever recorded during the month of May since record keeping began in Denver in 1872.   We have to go all the way back to May 3, 1907 to find a reading that low during May.

Here in Thornton we were quite cold as well although not quite as much as DIA.  Our morning low temperature of 20.7 degrees was seen at 6:00am.

The cold and snowy start to May mimics what was seen during the month of April.  Last month Denver recorded its fifth coldest and 11th snowiest April on record.

April 2013 weather recap: Another cold, snowy month

When we look back at April 2013 it will be remembered for two key things: the cold and the snow.  By both measurements the month saw extremes with temperatures well below normal and well above normal snowfall, the third month in a row we experienced those conditions.

A series of storm systems moved through during April providing regular doses of cold and snow.  Three systems from the 9th of the month through the 25th, each coming at the start of the workweeks, provided the notable conditions.  Seventeen of those 18 days saw below normal temperatures.

Denver’s official average temperature for the month came in at 41.7 degrees.  This was an impressive 5.7 degrees below the 1981 – 2000 historical average.  This put April 2013 into the books as the fifth coldest April since recordkeeping began in Denver.  Thornton was only slightly better with an April average temperature of 42.3 degrees.

On four days Denver failed to see high temperatures climb above freezing, Thornton registered three such days.

Five cold temperature records were setting during the month.  Record lows were set on April 9th, April 10th and April 22nd.  The record low was tied on April 16th.  A record low maximum was recorded on the 9th as well.

Temperatures ranged from a high of 80 degrees on the 29th down to a low of 6 degrees on the 10th in Denver.  Thornton’s temperatures were similar with a high of 81.7 degrees on the 29th and a low temperature for the month of 6.7 degrees on the 10th.

The precipitation was the second half of the April 2013 story with plenty of that falling, primarily in the form of snow.

Denver officially recorded 1.87 inches of liquid precipitation, just a bit above the April average of 1.71 inches.  Thornton was just a touch drier with 1.77 inches of precipitation.

Snow was in abundance as Denver saw 20.4 inches of snowfall as measured at Denver International Airport.  Thornton was trailing with 19.1 inches.  Both marks were well above the Denver April normal of 6.8 inches.  Denver’s measurement fell just short of making the list of 10 snowiest Aprils with April 2013 ranking as the 11th snowiest.

Click here to view the ThorntonWeather.com April 2013 Climate Summary

Thornton, Colorado April 2013 Temperatures.
Thornton, Colorado April 2013 Temperatures.
Thornton, Colorado April 2013 precipitation.
Thornton, Colorado April 2013 precipitation.

From the National Weather Service:

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF APRIL 2013...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2013

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              90   04/30/1992
 LOW               -2   04/02/1975
HIGHEST            80   04/29        83      -3       88  04/24
LOWEST              6   04/10        -2       8       24  04/07
AVG. MAXIMUM     54.7              61.5    -6.8     68.6
AVG. MINIMUM     28.7              33.3    -4.6     37.9
MEAN             41.7              47.4    -5.7     53.3
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      4               0.3     3.7        0
DAYS MIN <= 32     17              13.0     4.0        4
DAYS MIN <= 0       0               0.0     0.0        0 
PRECIPITATION (INCHES) 
RECORD  
 MAXIMUM         8.24   1900  
 MINIMUM         0.03   1963 
TOTALS           1.87              1.71    0.16     1.39 
DAILY AVG.       0.06              0.06    0.00     0.05 
DAYS >= .01        13               9.1     3.9        8
DAYS >= .10         7               4.5     2.5        4
DAYS >= .50         0               0.9    -0.9        0
DAYS >= 1.00        0               0.5    -0.5        0
GREATEST
 24 HR. TOTAL    0.50   04/22 TO 04/23           04/26 TO 04/27

SNOWFALL (INCHES)
RECORDS
 TOTAL           33.8  1933
TOTALS           20.4               6.8

DEGREE_DAYS
HEATING TOTAL     690               529     161      352
 SINCE 7/1       5802              5731      71     5215
COOLING TOTAL       0                 1      -1        6
 SINCE 1/1          0                 1      -1        6

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
....................................................

WIND (MPH)
AVERAGE WIND SPEED              11.0
RESULTANT WIND SPEED/DIRECTION   1/016
HIGHEST WIND SPEED/DIRECTION    49/290    DATE  04/14
HIGHEST GUST SPEED/DIRECTION    55/350    DATE  04/08

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.70
NUMBER OF DAYS FAIR            2
NUMBER OF DAYS PC             20
NUMBER OF DAYS CLOUDY          8

AVERAGE RH (PERCENT)     53

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              1     MIXED PRECIP               0
HEAVY RAIN                1     RAIN                       3
LIGHT RAIN               10     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                3     SNOW                       6
LIGHT SNOW                8     SLEET                      0
FOG                      12     FOG W/VIS <= 1/4 MILE      5
HAZE                     11

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

Thornton’s May weather preview: Everything from wintry weather to severe weather possible

Thornton, Colorado May 2013 weather preview.
Thornton, Colorado May 2013 weather preview.

Colorado’s famously highly variable weather seems to showcase itself during the month of May when a variety of weather conditions can be seen.

Winter-like temperatures and snow are possible as are mid-summer like temperatures or the more typical spring severe weather.

As the month starts out in 2013 we are going to receive a wintry blast with cold and snow.  This is not entirely unusual as Denver averages 1.7 inches of snow during the month since records began.

More common however is severe weather, particularly in the latter half of the month.  Thunderstorms become more frequent and their associated hazards – lightning, wind, hail and tornadoes – are usual visitors.

For a complete look at what lies ahead for the month of May, check out our full preview here.

March 2013 Thornton weather recap: Cool month brings much-needed precipitation

With snowpack lagging and spring set to arrive, hopes were high that March could bring some relief to Colorado’s parched landscape and Mother Nature did oblige.  March 2013 brought above average snowfall and cooler than normal temperatures.

The month started out with near normal temperatures but the first in a series of disturbances throughout the month arrived on the 4th.  A couple of inches was delivered to the area on the date which was followed by a few days of mild weather.

The warmth did not last as another storm system which began a repeating pattern across the month with mild temperatures followed by periods of cold and snow.

Thornton’s overall average temperature for the month came in at 38.3 degrees.  At Denver’s official weather station at Denver International Airport the month averaged 37.7 degrees.  Both locations’ average temperatures were below the March historical average (1981 to 2010) of 40.4 degrees.

We recorded 25 days with low temperatures dropping below the freezing mark.  Three days saw high temperatures fail to climb above 32 degrees.

Our warmest temperature during March 2013 was a reading of 78.6 degrees on the 15th.  The coldest reading was on the 24th when the mercury dropped to a bone-chilling 2 degrees.  Out at DIA, the warmest reading was 76 degrees on the 15th and the coldest was 2 degrees on the 25th.

In terms of precipitation, Thornton saw 1.45 inches in the rain bucket, almost all from snow.  Denver’s numbers were near identical at 1.47 inches.  Both were well above the March average of 0.92 inch.

Snowfall was the big story for the month as Thornton recorded 20.2 inches of the white stuff.  Out at DIA the Mile High City saw even more as it measured 23.5 inches.  March historically averages 10.7 inches so we were well above normal while the month’s reputation as our snowiest month of the year held true.

The month did come very close to making the list of ‘top 10 snowiest Marches.’  The number 10 spot on that list came in 1981 when 24.0 inches was recorded.

Despite the cold and snow, only one weather record was set during the month.  The 11.6 inches of snow recorded at DIA from the 22nd to the 23rd set a two-day snowfall total record for the date, besting the previous mark of 8.0 inches set in 2010.

Click here to view the ThorntonWeather.com March 2013 Climate Summary

2013-03-Temps.jpg
Thornton, Colorado March 2013 Temperatures
2013-03-Precip.jpg
Thornton, Colorado March 2013 Precipitation
...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF MARCH 2013...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2013

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              84   03/26/1971
 LOW              -11   03/28/1886
HIGHEST            76   03/15        84      -8       81  03/31
LOWEST              2   03/25       -11      13       16  03/02
AVG. MAXIMUM     50.7              54.4    -3.7     65.5
AVG. MINIMUM     24.6              26.4    -1.8     32.9
MEAN             37.7              40.4    -2.7     49.2
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX = .01         6               5.9     0.1        2
DAYS >= .10         4               2.4     1.6        0
DAYS >= .50         0               0.3    -0.3        0
DAYS >= 1.00        0               0.1    -0.1        0
GREATEST
 24 HR. TOTAL    0.47   03/22 TO 03/22           03/01 TO 03/02
                                                          03/01 TO 03/01
                                                          03/01 TO 03/01
 STORM TOTAL       MM                                 MM
 (MM/DD(HH))            MM                    03/02(00) TO 03/02(00)
                                                 03/01(00) TO 03/01(00)1
                                                 03/01(00) TO 03/01(00)1

SNOWFALL (INCHES)
RECORDS
 TOTAL             MM   5
TOTALS           23.5              10.7

DEGREE_DAYS
HEATING TOTAL     840               763      77      483
 SINCE 7/1       5112              5202     -90     4863
COOLING TOTAL       0                 0       0        0
 SINCE 1/1          0                 0       0        0

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST      03/01             10/07
LATEST                          05/05
..................................................

WIND (MPH)
AVERAGE WIND SPEED              10.1
RESULTANT WIND SPEED/DIRECTION   1/223
HIGHEST WIND SPEED/DIRECTION    38/010    DATE  03/09
HIGHEST GUST SPEED/DIRECTION    47/280    DATE  03/17

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR            2
NUMBER OF DAYS PC             20
NUMBER OF DAYS CLOUDY          9

AVERAGE RH (PERCENT)     53

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       0
LIGHT RAIN                1     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                3     SNOW                       5
LIGHT SNOW                8     SLEET                      0
FOG                       9     FOG W/VIS