Thornton’s December was lacking in terms of any sort of real weather drama. Temperatures were relatively mild for much of the month and precipitation was fleeting.
Above normal temperatures were the general rule for the first part of the month. It was only the last week of the month when Arctic air arrived and we saw temperatures drop considerably. We saw only two measurable snow events, neither of which amounted to much.
Overall, Thornton’s average temperature for the month was 30.8 degrees. This was nearly a full degree above Denver’s long term December average of 30.0 degrees. Out at DIA where the Mile High City’s official measurements are taken, it was a good bit warmer with an average of 32.5 degrees.
Temperatures in Thornton ranged from a high of 60.6 degrees on the 21st down to a low of 4.5 degrees on the morning of the 29th. Denver’s warmest reading of 63 degrees also came on the 21st and its coldest, 0 degrees, on the 31st.
Denver averages 0.35 inches of precipitation during December. Thornton fell well short with a mere 0.07 inches. Out at the airport, even less was realized with 0.03 being recorded. This puts December 2018 into the books as one of the driest Decembers ever recorded.
Ten driest December’s in Denver weather history (since 1872):
INCHES
0.00 – 1881
TRACE – 1905
0.01 – 1906, 1895
0.03 – 1977, 1931, 2018
0.04 – 2004, 1890
0.05 – 2002, 1995
Thornton recorded a mere 0.9 inches of snow during the month, the majority of which fell on the last day of the month. Denver saw 0.5 inches, all on the 31st. Both fall well short of the long term Denver average for December snowfall of 8.5 inches and put December 2018 on the list of the ten least snowy Decembers recorded.
Ten least snowy December’s in Denver weather history:
TRACE – 1905, 1906, 2002
0.1 – 1928
0.4 – 1890
0.5 – 1935, 2018
0.6 – 1995
0.7 – 1977, 1895
Click here to view Thornton’s December 2018 climate report.
CLIMATE REPORT
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
936 AM MST TUE JAN 1 2019
...................................
...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF DECEMBER 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 79 12/05/1939
LOW -25 12/22/1990
12/24/1876
HIGHEST 63 12/21 62 1 69 12/12
LOWEST 0 12/31 -4 4 -4 12/24
AVG. MAXIMUM 46.1 42.8 3.3 48.3
AVG. MINIMUM 18.8 17.1 1.7 18.0
MEAN 32.5 30.0 2.5 33.2
DAYS MAX >= 90 0 0.0 0.0 0
DAYS MAX <= 32 4 5.8 -1.8 4
DAYS MIN <= 32 31 29.4 1.6 28
DAYS MIN <= 0 1 2.0 -1.0 1
PRECIPITATION (INCHES)
RECORD
MAXIMUM 5.21 1913
MINIMUM 0.00 1881
TOTALS 0.03 0.35 -0.32 0.21
DAILY AVG. 0.00 0.01 -0.01 0.01
DAYS >= .01 1 4.1 -3.1 4
DAYS >= .10 0 1.1 -1.1 1
DAYS >= .50 0 0.1 -0.1 0
DAYS >= 1.00 0 0.0 0.0 0
GREATEST
24 HR. TOTAL 0.03 12/31 TO 12/31
SNOWFALL (INCHES)
TOTALS 0.5 8.5
DEGREE_DAYS
HEATING TOTAL 999 1086 -87 979
SINCE 7/1 2372 2468 -96 2150
COOLING TOTAL 0 0 0 0
SINCE 1/1 1026 769 257 881
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 2/222
HIGHEST WIND SPEED/DIRECTION 39/010 DATE 12/12
HIGHEST GUST SPEED/DIRECTION 53/010 DATE 12/12
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.50
NUMBER OF DAYS FAIR 6
NUMBER OF DAYS PC 22
NUMBER OF DAYS CLOUDY 3
AVERAGE RH (PERCENT) 51
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.