428
CXUS55 KRIW 012023
CLMGEY
CLIMATE REPORT
NATIONAL WEATHER SERVICE RIVERTON WY
212 PM MDT WED OCT 01 2025
...PRELIMINARY MONTHLY CLIMATE SUMMARY FOR GREYBULL FOR THE MONTH OF
SEPTEMBER 2025...
...OFFICIAL CLIMATE DATA FOR THE MONTH OF SEPTEMBER 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 SEPTEMBER WAS DRIER AND WARMER THAN NORMAL.
THE AVERAGE TEMPERATURE FOR GREYBULL IN SEPTEMBER WAS 64.4 DEGREES
WHICH IS 3.5 DEGREES ABOVE NORMAL. IT WAS THE 4TH WARMEST SEPTEMBER
SINCE RECORDS BEGAN IN 1998. THE WARMEST TEMPERATURE FOR THE MONTH
WAS 93 DEGREES ON THE 2ND. THE HIGH OF 89 ON THE 21ST BROKE 86
DEGREES FROM 2013. THE COLDEST TEMPERATURE WAS 39 DEGREES ON THE 6TH
AND BROKE THE 2015 RECORD OF 40 DEGREES.
PRECIPITATION FOR THE MONTH WAS 0.65 INCHES...WHICH IS 78 PERCENT OF
NORMAL. THE WETTEST 24-HOUR PERIOD OCCURRED ON THE 22ND WITH 0.53
INCHES AND BROKE THE 2023 RECORD OF 0.31. THE HIGHEST WIND GUST WAS
45 MPH. IT OCCURRED ON THE 4TH AND ON THE 7TH...BOTH FROM THE
NORTHWEST.
..THE GREYBULL WY CLIMATE SUMMARY FOR THE MONTH OF SEPTEMBER 2025
CLIMATE NORMAL PERIOD: 1991 TO 2020
CLIMATE RECORD PERIOD: 1998 TO 2025
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S
VALUE DATE(S) VALUE FROM VALUE
NORMAL
..........................................................
TEMPERATURE (F)
RECORD
HIGH 103 09/04/2022
LOW 27 09/18/2003
09/29/1999
HIGHEST 93 09/02
LOWEST 39 09/06
AVG. MAXIMUM 81.4 76.7 4.7
AVG. MINIMUM 47.4 45.1 2.3
MEAN 64.4 60.9 3.5
DAYS MAX >= 90 4
DAYS MAX <= 32 0
DAYS MIN <= 32 0
DAYS MIN <= 0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 3.21 2019
MINIMUM 0.01 2021
TOTALS 0.65 0.83 -0.18 0.38
DAILY AVG. 0.02 0.03 -0.01
DAYS >= .01 4
DAYS >= .10 1
DAYS >= .50 1
DAYS >= 1.00 0
GREATEST
24 HR. TOTAL 0.53 09/22 TO 09/22
STORM TOTAL 0.53
DEGREE DAYS
HEATING TOTAL 61 169 -108
SINCE 7/1 61 189 -128
COOLING TOTAL 50 46 4
SINCE 1/1 791 742 49
..........................................................
WIND (MPH)
AVERAGE WIND SPEED 5.5
RESULTANT WIND SPEED/DIRECTION 1/320
HIGHEST WIND SPEED/DIRECTION 35/340 DATE 09/04
HIGHEST GUST SPEED/DIRECTION 45/330 DATE 09/04
45/310 09/07
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.12
NUMBER OF DAYS FAIR 26
NUMBER OF DAYS PC 4
NUMBER OF DAYS CLOUDY 0
AVERAGE RH (PERCENT) 50
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 3 MIXED PRECIP 0
HEAVY RAIN 0 RAIN 1
LIGHT RAIN 6 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 0
HEAVY SNOW 0 SNOW 0
LIGHT SNOW 0 SLEET 0
FOG 5 FOG W/VIS <= 1/4 MILE 1
HAZE 0
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
LOOKING AHEAD TO OCTOBER 2025. THE AVERAGE HIGH TEMPERATURE ON THE
FIRST OF THE MONTH IS 68 DEGREES...AND THE AVERAGE LOW TEMPERATURE
IS 39 DEGREES. THE AVERAGE HIGH BY THE END OF THE MONTH IS 52
DEGREES...AND THE AVERAGE LOW TEMPERATURE IS 26 DEGREES. THE AVERAGE
MONTHLY PRECIPITATION IS 0.60 INCHES.
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