For the second time in the past three months, Denver has experienced monthly average temperatures in the ‘top 10 coldest’ category. In October, the Mile High City saw its second coldest October on record since record keeping began in 1882. Now Denver has just wrapped up its seventh coldest December in history.
Denver’s average December 2009 temperature was 24.1 degrees – a chilly 6.2 degrees below the normal average of 30.3 degrees. That puts the month into the books as the seventh coldest December on record (image right). Thornton was just a touch colder having recorded an average temperature of 23.8 degrees.
Temperatures during the month ranged from a high temperature of 59 degrees on the 1st down to a low of -17 on the 9th. Overall, the majority of days during the month saw below normal temperatures.
In terms of snowfall, the month did finish above average but not in record setting territory. The National Weather Service recorded 11.1 inches of snowfall at the official monitoring station at Denver International Airport. This was 2.4 inches above the average of 8.7 inches for December. In Thornton, we received a bit more snow than DIA. 15.3 inches was recorded at ThorntonWeather.com of which the single biggest even was the pre-Christmas storm which dumped 7.5 inches.
The snow we did receive however was rather dry and as such we finished the month below normal for precipitation. DIA recorded 0.45 inch of precipitation which is 0.18 inch below normal. Here again, because of the additional snowfall, Thornton fared a bit better with 0.5 inch of precipitation.
CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
510 PM MST SAT JAN 2 2010
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...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF DECEMBER 2009...
CLIMATE NORMAL PERIOD 1971 TO 2000
CLIMATE RECORD PERIOD 1872 TO 2009
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S
VALUE DATE(S) VALUE FROM VALUE DATE(S)
NORMAL
................................................................
TEMPERATURE (F)
RECORD
HIGH 79 12/05/1939
LOW -25 12/22/1990
12/24/1876
HIGHEST 59 12/21 79 -20 69 12/02
12/01
LOWEST -17 12/09 -25 8 -19 12/15
AVG. MAXIMUM 36.4 44.1 -7.7 41.0
AVG. MINIMUM 11.9 16.4 -4.5 12.3
MEAN 24.1 30.3 -6.2 26.6
DAYS MAX >= 90 0 0.0 0.0 0
DAYS MAX <= 32 15 5.3 9.7 10
DAYS MIN <= 32 31 29.2 1.8 30
DAYS MIN <= 0 6 2.8 3.2 6
PRECIPITATION (INCHES)
RECORD
MAXIMUM 5.21 1913
MINIMUM 0.00 1881
TOTALS 0.45 0.63 -0.18 0.24
DAILY AVG. 0.01 0.02 -0.01 0.01
DAYS >= .01 7 5.3 1.7 6
DAYS >= .10 2 MM MM 0
DAYS >= .50 0 MM MM 0
DAYS >= 1.00 0 MM MM 0
GREATEST
24 HR. TOTAL 0.20 12/22 TO 12/23 0.10 12/13 TO 12/14
SNOWFALL (INCHES)
RECORDS
TOTAL 57.4 1913 SNOWIEST DENVER MONTH SINCE 1881
TOTALS 11.1 8.7 7.1
DEGREE_DAYS
HEATING TOTAL 1260 1078 182 1179
SINCE 7/1 2739 2486 253 2367
COOLING TOTAL 0 0 0 0
SINCE 1/1 533 696 -163 825
FREEZE DATES
RECORD
EARLIEST 09/08/1962
LATEST 06/08/2007
EARLIEST 10/07
LATEST 05/05
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WIND (MPH)
AVERAGE WIND SPEED 8.8
RESULTANT WIND SPEED/DIRECTION 3/217
HIGHEST WIND SPEED/DIRECTION 43/220 DATE 12/13
HIGHEST GUST SPEED/DIRECTION 49/220 DATE 12/13
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM *SUNSHINE DATA N/A EFFECTIVE 10/1
NUMBER OF DAYS FAIR 4
NUMBER OF DAYS PC 21
NUMBER OF DAYS CLOUDY 6
AVERAGE RH (PERCENT) 61
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 0 MIXED PRECIP 0
HEAVY RAIN 0 RAIN 0
LIGHT RAIN 0 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 0
HEAVY SNOW 0 SNOW 2
LIGHT SNOW 10 SLEET 0
FOG 11 FOG W/VIS <= 1/4 MILE 1
HAZE 7
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.