759
CXUS55 KRIW 011718
CLMRIW
CLIMATE REPORT
NATIONAL WEATHER SERVICE RIVERTON WY
1105 AM MDT THU OCT 01 2026
...PRELIMINARY MONTHLY CLIMATE SUMMARY FOR RIVERTON FOR THE MONTH OF
SEPTEMBER 2026...
...OFFICIAL CLIMATE DATA FOR THE MONTH OF SEPTEMBER 2026 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
..RIVERTON WAS WARMER AND WETTER THAN NORMAL IN SEPTEMBER
THE AVERAGE TEMPERATURE FOR RIVERTON IN SEPTEMBER WAS 63.4 DEGREES
WHICH WAS 4.2 DEGREES ABOVE NORMAL. IT WAS THE 4TH WARMEST SEPTEMBER
ON RECORD. THE WARMEST READING FOR THE MONTH WAS 89 DEGREES ON THE
5TH AND 6TH. THE COLDEST READING WAS 40 DEGREES ON THE 15TH. NO
TEMPERATURE RECORDS WERE BROKEN THIS MONTH.
PRECIPITATION FOR THE MONTH WAS 1.55 INCHES...WHICH IS 201 PERCENT
OF NORMAL. THE WETTEST 24-HOURS WAS THE 19TH WHEN 0.77 INCHES FELL.
THIS BROKE THE 1999 RECORD OF 0.46. THE 20TH HAD 0.57 INCHES AND
BROKE 0.39 FROM 1998. THE HIGHEST WIND GUST WAS 55 MPH FROM THE
NORTHWEST ON THE 14TH.
..THE RIVERTON WY CLIMATE SUMMARY FOR THE MONTH OF SEPTEMBER 2026
CLIMATE NORMAL PERIOD: 1991 TO 2020
CLIMATE RECORD PERIOD: 1995 TO 2026
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S
VALUE DATE(S) VALUE FROM VALUE
NORMAL
..........................................................
TEMPERATURE (F)
RECORD
HIGH 100 09/04/2022
LOW 21 09/27/1996
09/27/1996
HIGHEST 89 09/05
09/06
LOWEST 40 09/15
AVG. MAXIMUM 77.8 74.0 3.8
AVG. MINIMUM 49.0 44.4 4.6
MEAN 63.4 59.2 4.2
DAYS MAX >= 90 0
DAYS MAX <= 32 0
DAYS MIN <= 32 0
DAYS MIN <= 0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 3.01 2013
MINIMUM 0.01 2010
TOTALS 1.55 0.77 0.78 0.99
DAILY AVG. 0.05 0.03 0.02
DAYS >= .01 5
DAYS >= .10 3
DAYS >= .50 2
DAYS >= 1.00 0
GREATEST
24 HR. TOTAL 0.77 09/19 TO 09/19
STORM TOTAL 0.77
SNOWFALL (INCHES)
TOTALS 0.0 MM MM
SINCE 7/1 0.0 MM MM
SNOWDEPTH AVG. 0
DAYS >= 1.0 0
DEGREE DAYS
HEATING TOTAL 85 205 -120
SINCE 7/1 87 241 -154
COOLING TOTAL 44 31 13
SINCE 1/1 757 499 258
..........................................................
WIND (MPH)
AVERAGE WIND SPEED 8.7
RESULTANT WIND SPEED/DIRECTION 2/270
HIGHEST WIND SPEED/DIRECTION 38/320 DATE 09/14
HIGHEST GUST SPEED/DIRECTION 55/310 DATE 09/14
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.11
NUMBER OF DAYS FAIR 28
NUMBER OF DAYS PC 2
NUMBER OF DAYS CLOUDY 0
AVERAGE RH (PERCENT) 46
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 4 MIXED PRECIP 0
HEAVY RAIN 0 RAIN 3
LIGHT RAIN 10 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 0
HEAVY SNOW 0 SNOW 0
LIGHT SNOW 0 SLEET 0
FOG 3 FOG W/VIS <= 1/4 MILE 0
HAZE 1
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
LOOKING AHEAD TO OCTOBER 2026. THE AVERAGE HIGH TEMPERATURE ON THE
FIRST OF THE MONTH IS 66 DEGREES...AND THE AVERAGE LOW TEMPERATURE
IS 38 DEGREES. THE AVERAGE HIGH AT THE END OF THE MONTH IS 51
DEGREES AND THE AVERAGE LOW TEMPERATURE IS 25. THE AVERAGE MONTHLY
PRECIPITATION IS 0.83 INCHES.
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