080
CXUS55 KRIW 092103 CCA
CLMCPR
CLIMATE REPORT
NATIONAL WEATHER SERVICE RIVERTON WY
121 PM MST FRI JAN 09 2026
...PRELIMINARY MONTHLY CLIMATE SUMMARY FOR CASPER FOR THE MONTH OF
DECEMBER 2025...
...OFFICIAL CLIMATE DATA FOR THE MONTH OF DECEMBER 2025 WILL BE
AVAILABLE IN APPROXIMATELY 60 DAYS FROM THE NATIONAL CENTERS FOR
ENVIRONMENTAL INFORMATION (HTTP://WWW.NCDC.NOAA.GOV/CDO-
WEB/DATASETS). UNOFFICIAL ASOS DAILY SUMMARIES ARE AVAILABLE ON THE
INTERNET AT HTTP://WWW.WEATHER.GOV/CLIMATE/INDEX.PHP?WFO=RIW
..DECEMBER WAS DRIER WITH RECORD WARMTH FOR CASPER
AVERAGE TEMPERATURE FOR CASPER IN DECEMBER WAS 36.9 DEGREES WHICH IS
12.1 DEGREES ABOVE NORMAL. IT WAS THE WARMEST DECEMBER ON RECORD.
THE WARMEST READING OF THE MONTH WAS 63 DEGREES ON THE 23RD WHICH
BROKE THE 1994 RECORD OF 53 AND ON THE 24TH WHICH BROKE THE 1955
RECORD OF 52 DEGREES. ADDITIONAL DAILY HIGH TEMPERATURE RECORDS WERE
BROKEN AND ARE LISTED BELOW. THE COLDEST READING FOR THE MONTH WAS
10 DEGREES BELOW ZERO ON THE 28TH.
DATE NEWOLDYEAR
11TH 60591939
14TH 59551998
15TH 59571980
16TH 60591980
19TH 59552023
21ST 57(T)572024
22ND 61551940
25TH 61561980
TOTAL PRECIPITATION FOR THE MONTH WAS 0.36 INCHES...WHICH IS 59
PERCENT OF NORMAL. THE WETTEST 24-HOUR PERIOD DURING THE MONTH WAS
ON THE 26TH-27TH WITH 0.15 INCHES. NO PRECIPITATION OR SNOWFALL
RECORDS WERE BROKEN THIS MONTH.
THE SNOWFALL FOR THE MONTH WAS 5.5 INCHES WHICH IS 50 PERCENT OF
NORMAL. THE SNOWIEST 24-HOURS WAS ON THE 27TH-28TH WITH 2.5 INCHES.
THE HIGHEST WIND GUST WAS 78 MPH FROM THE NORTHWEST ON THE 17TH.
THERE WAS A GUST OF 76 MPH FROM THE SOUTHWEST ON THE 19TH.
..THE CASPER WY CLIMATE SUMMARY FOR THE MONTH OF DECEMBER 2025
CLIMATE NORMAL PERIOD: 1991 TO 2020
CLIMATE RECORD PERIOD: 1939 TO 2026
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S
VALUE DATE(S) VALUE FROM VALUE
NORMAL
..........................................................
TEMPERATURE (F)
RECORD
HIGH 66 12/02/2021
LOW -42 12/22/2022
HIGHEST 63 12/23
12/24
LOWEST -10 12/28
AVG. MAXIMUM 48.1R 34.7 13.4
AVG. MINIMUM 25.6R 14.8 10.8
MEAN 36.9R 24.8 12.1
DAYS MAX >= 90 0
DAYS MAX <= 32 3
DAYS MIN <= 32 24
DAYS MIN <= 0 1
PRECIPITATION (INCHES)
RECORD
MAXIMUM 3.71 1982
MINIMUM 0.03 1952
TOTALS 0.36 0.61 -0.25 0.16
DAILY AVG. 0.01 0.02 -0.01
DAYS >= .01 6
DAYS >= .10 2
DAYS >= .50 0
DAYS >= 1.00 0
GREATEST
24 HR. TOTAL 0.15 12/26 TO 12/27
STORM TOTAL 0.13
SNOWFALL (INCHES)
TOTALS 5.5 11.0 -5.5
SINCE 7/1 9.8 28.4 -18.6
SNOWDEPTH AVG. 0
DAYS >= 1.0 4
DEGREE DAYS
HEATING TOTAL 863 1248 -385
SINCE 7/1 2289 3048 -759
COOLING TOTAL 0 0 0
SINCE 1/1 467 443 24
..........................................................
WIND (MPH)
AVERAGE WIND SPEED 17.1
RESULTANT WIND SPEED/DIRECTION 15/230
HIGHEST WIND SPEED/DIRECTION 58/250 DATE 12/19
HIGHEST GUST SPEED/DIRECTION 78/290 DATE 12/17
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.23
NUMBER OF DAYS FAIR 22
NUMBER OF DAYS PC 9
NUMBER OF DAYS CLOUDY 0
AVERAGE RH (PERCENT) 56
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 1 MIXED PRECIP 0
HEAVY RAIN 0 RAIN 0
LIGHT RAIN 7 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 0
HEAVY SNOW 0 SNOW 1
LIGHT SNOW 10 SLEET 0
FOG 8 FOG W/VIS <= 1/4 MILE 0
HAZE 3
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
LOOKING AHEAD TO JANUARY 2026. THE AVERAGE HIGH TEMPERATURE ON THE
FIRST OF THE MONTH IS 34 DEGREES...AND THE AVERAGE LOW TEMPERATURE
IS 14 DEGREES. THE AVERAGE HIGH BY THE END OF THE MONTH IS 36
DEGREES...AND THE AVERAGE LOW TEMPERATURE IS 15. THE AVERAGE MONTHLY
PRECIPITATION IS 0.49 INCHES. THE AVERAGE SNOWFALL IS 9 INCHES.
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