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CXUS55 KRIW 092042 CCA
CLMGEY
CLIMATE REPORT
NATIONAL WEATHER SERVICE RIVERTON WY
121 PM MST FRI JAN 09 2026
...PRELIMINARY MONTHLY CLIMATE SUMMARY FOR GREYBULL 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
..GREYBULL IN DECEMBER WAS WETTER WITH RECORD WARMTH.
THE AVERAGE TEMPERATURE FOR GREYBULL IN DECEMBER WAS 32.8 DEGREES
WHICH IS 13.5 DEGREES ABOVE NORMAL. IT WAS THE WARMEST DECEMBER
SINCE RECORDS BEGAN IN 1998. THE WARMEST TEMPERATURE FOR THE MONTH
WAS 65 DEGREES ON THE 24TH...WHICH BROKE THE 2019 RECORD OF 50. THIS
ALSO SET A NEW ALL-TIME MONTHLY HIGH TEMPERATURE FOR DECEMBER. THE
OLD RECORD WAS 64 DEGREES SET IN 1998. SEVERAL OTHER DAILY HIGH
RECORDS WERE BROKEN AND ARE LISTED BELOW. THE COLDEST TEMPERATURE
WAS 4 DEGREES ON THE 1ST.
DATENEWOLDYEAR
16TH59451998
17TH59511998
19TH56492024
25TH60452020
26TH57451998
27TH48472022
PRECIPITATION FOR THE MONTH WAS 0.24 INCHES...WHICH IS 218 PERCENT
OF NORMAL. IT WAS THE 4TH WETTEST DECEMBER ON RECORD. THE WETTEST 24-
HOUR PERIOD OCCURRED FROM THE 5TH TO THE 6TH WITH 0.12 INCHES. THE
5TH HAD 0.09 INCHES AND BROKE THE 2005 RECORD OF 0.07. THE 6TH HAD
0.09 INCHES AND BROKE 0.01 FROM 2008. THE 9TH HAD 0.02 INCHES AND
BROKE A TRACE FROM 2024, 2023 AND 2019. THE HIGHEST WIND GUST WAS 70
MPH. IT OCCURRED ON THE 17TH FROM THE NORTHWEST.
..THE GREYBULL WY CLIMATE SUMMARY FOR THE MONTH OF DECEMBER 2025
CLIMATE NORMAL PERIOD: 1991 TO 2020
CLIMATE RECORD PERIOD: 1998 TO 2026
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S
VALUE DATE(S) VALUE FROM VALUE
NORMAL
..........................................................
TEMPERATURE (F)
RECORD
HIGH 64 12/01/1998
LOW -36 12/22/2022
HIGHEST 65R 12/24
LOWEST 4 12/01
AVG. MAXIMUM 44.6 30.8 13.8
AVG. MINIMUM 20.9 7.9 13.0
MEAN 32.8 19.3 13.5
DAYS MAX >= 90 0
DAYS MAX <= 32 2
DAYS MIN <= 32 30
DAYS MIN <= 0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 0.49 1999
MINIMUM T 2023
TOTALS 0.24 0.11 0.13 0.23
DAILY AVG. 0.01 0.00 0.01
DAYS >= .01 4
DAYS >= .10 0
DAYS >= .50 0
DAYS >= 1.00 0
GREATEST
24 HR. TOTAL 0.12 12/05 TO 12/06
STORM TOTAL 0.09
DEGREE DAYS
HEATING TOTAL 992 1415 -423
SINCE 7/1 2365 3194 -829
COOLING TOTAL 0 0 0
SINCE 1/1 791 744 47
..........................................................
WIND (MPH)
AVERAGE WIND SPEED 5.8
RESULTANT WIND SPEED/DIRECTION 1/190
HIGHEST WIND SPEED/DIRECTION 53/290 DATE 12/17
HIGHEST GUST SPEED/DIRECTION 70/300 DATE 12/17
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.33
NUMBER OF DAYS FAIR 18
NUMBER OF DAYS PC 9
NUMBER OF DAYS CLOUDY 4
AVERAGE RH (PERCENT) 66
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 0 MIXED PRECIP 0
HEAVY RAIN 0 RAIN 0
LIGHT RAIN 5 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 0
HEAVY SNOW 0 SNOW 1
LIGHT SNOW 5 SLEET 0
FOG 6 FOG W/VIS <= 1/4 MILE 1
HAZE 1
- 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 29 DEGREES...AND THE AVERAGE LOW TEMPERATURE
IS 6 DEGREES. THE AVERAGE HIGH BY THE END OF THE MONTH IS 30
DEGREES... AND THE AVERAGE LOW TEMPERATURE IS 7 DEGREES. THE AVERAGE
MONTHLY PRECIPITATION IS 0.15 INCHES.
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