623
CXUS55 KRIW 092046 CCA
CLMP60
CLIMATE REPORT
NATIONAL WEATHER SERVICE RIVERTON WY
121 PM MST FRI JAN 09 2026
...PRELIMINARY MONTHLY CLIMATE SUMMARY FOR LAKE YELLOWSTONE FOR THE
MONTH OF DECEMBER 2025...
...OFFICIAL CLIMATE DATA FOR THE MONTH OF DECEMBER 2025 WILL BE
AVAILABLE APPROXIMATELY IN 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
..LAKE YELLOWSTONE WAS WETTER WITH RECORD WARMTH IN DECEMBER
AVERAGE TEMPERATURE FOR LAKE YELLOWSTONE IN DECEMBER WAS 23.2
DEGREES WHICH IS 10.2 DEGREES ABOVE NORMAL. IT WAS THE WARMEST
DECEMBER SINCE RECORDS BEGAN IN 1998. THE WARMEST READING OF THE
MONTH WAS 42 DEGREES ON THE 15TH AND BROKE THE 2006 RECORD OF 25.
SEVERAL OTHER DAILY HIGH RECORDS WERE BROKEN AND ARE LISTED BELOW.
THE COLDEST READING OF THE MONTH WAS -15 DEGREES ON THE 28TH.
DATENEW OLDYEAR
10TH36(T)362004/2014
13TH40 371998
14TH40 381998
16TH39 372018
23RD39 372019
24TH39 342024
25TH37 32 1999
TOTAL PRECIPITATION AT LAKE YELLOWSTONE WAS 5.42 INCHES...WHICH WAS
231 PERCENT OF NORMAL. IT WAS THE 2ND WETTEST DECEMBER SINCE
RECORDS BEGAN IN 1998. THE WETTEST 24-HOUR PERIOD DURING THE MONTH
WAS THE 24TH-25TH WHEN 1.12 INCHES OF PRECIPITATION FELL. THERE WERE
A FEW DAILY PRECIPITATION RECORDS BROKEN AND ARE LISTED BELOW. THE
HIGHEST WIND GUST WAS 53 MPH FROM THE WEST ON THE 17TH.
DATENEW OLD YEAR
21ST0.65”0.46”2015
22ND0.64”0.30”2021
24TH 0.45”0.36”2014
25TH0.91”0.36”2021
...THE LAKE YELLOWSTONE 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 46 12/12/2014
LOW -36 12/22/2022
HIGHEST 42 12/15
LOWEST -15 12/28
AVG. MAXIMUM 31.3 23.3 8.0
AVG. MINIMUM 15.2 2.7 12.5
MEAN 23.2 13.0 10.2
DAYS MAX >= 90 0
DAYS MAX <= 32 16
DAYS MIN <= 32 29
DAYS MIN <= 0 3
PRECIPITATION (INCHES)
RECORD
MAXIMUM 6.99 2010
MINIMUM 0.37 2000
TOTALS 5.42 2.35 3.07 1.33
DAILY AVG. 0.17 0.08 0.09
DAYS >= .01 20
DAYS >= .10 13
DAYS >= .50 4
DAYS >= 1.00 0
GREATEST
24 HR. TOTAL 1.12 12/24 TO 12/25
STORM TOTAL 0.91
DEGREE DAYS
HEATING TOTAL 1287 1612 -325
SINCE 7/1 4245 5119 -874
COOLING TOTAL 0 0 0
SINCE 1/1 1 0 1
..........................................................
WIND (MPH)
AVERAGE WIND SPEED 4.2
RESULTANT WIND SPEED/DIRECTION 1/250
HIGHEST WIND SPEED/DIRECTION 28/280 DATE 12/17
HIGHEST GUST SPEED/DIRECTION 53/260 DATE 12/17
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.00
NUMBER OF DAYS FAIR 31
NUMBER OF DAYS PC 0
NUMBER OF DAYS CLOUDY 0
AVERAGE RH (PERCENT) 78
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 0 MIXED PRECIP 0
HEAVY RAIN 0 RAIN 0
LIGHT RAIN 4 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 0
HEAVY SNOW 0 SNOW 0
LIGHT SNOW 19 SLEET 0
FOG 0 FOG W/VIS <= 1/4 MILE 0
HAZE 0
- 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 22 DEGREES...AND THE AVERAGE LOW TEMPERATURE
IS 1 DEGREES. THE AVERAGE HIGH BY THE END OF THE MONTH IS 23 DEGREES
AND THE AVERAGE LOW TEMPERATURE IS 0 DEGREES. THE AVERAGE MONTHLY
PRECIPITATION IS 1.80 INCHES.
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