Climatological Report (Monthly)
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
863
CXUS55 KRIW 011647
CLMRIW
CLIMATE REPORT
NATIONAL WEATHER SERVICE RIVERTON WY
1032 AM MDT MON JUN 01 2026
...PRELIMINARY MONTHLY CLIMATE SUMMARY FOR RIVERTON FOR THE MONTH OF
MAY 2026...
...OFFICIAL CLIMATE DATA FOR THE MONTH OF MAY 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 DRIER THAN NORMAL IN MAY....
THE AVERAGE TEMPERATURE FOR RIVERTON IN MAY WAS 55.8 DEGREES WHICH
WAS 2.6 DEGREES ABOVE NORMAL. IT WAS THE 7TH WARMEST MAY SINCE
RECORDS BEGAN IN 1996. THE WARMEST READING FOR THE MONTH WAS 91
DEGREES ON THE 13TH. THIS BROKE THE 2013 RECORD OF 87 AND SETS A NEW
RECORD FOR EARLIEST 90-DEGREE DAY. PREVIOUSLY IT WAS MAY 28TH 2003.
THE 11TH HIGH OF 86 BROKE 83 FROM 2007. THE COLDEST READING WAS 25
DEGREES ON THE 6TH AND BROKE THE 1999 RECORD OF 26. THE LOW OF 30
DEGREES ON THE 18TH BROKE 32 FROM 2017. THE LOW OF 29 DEGREES ON THE
19TH BROKE 31 FROM 2019.
PRECIPITATION FOR THE MONTH WAS 0.59 INCHES...WHICH IS 31 PERCENT OF
NORMAL. IT WAS THE 6TH DRIEST MAY ON RECORD. THE WETTEST 24-HOURS
WAS THE 21ST WHEN 0.29 INCHES FELL. NO PRECIPITATION OR SNOWFALL
RECORDS WERE BROKEN THIS MONTH.
SNOWFALL FOR THE MONTH WAS 0.8 INCHES. THE SNOWIEST 24-HOURS WAS ON
THE 5TH WHEN 0.5 INCHES FELL. THE HIGHEST WIND GUST WAS 60 MPH FROM
THE SOUTHWEST AND OCCURRED ON THE 13TH.
...THE RIVERTON WY CLIMATE SUMMARY FOR THE MONTH OF MAY 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 93 05/29/2003
LOW 19 05/09/2002
HIGHEST 91 05/13
LOWEST 25 05/06
AVG. MAXIMUM 70.5 66.8 3.7
AVG. MINIMUM 41.1 39.5 1.6
MEAN 55.8 53.2 2.6
DAYS MAX >= 90 1
DAYS MAX <= 32 0
DAYS MIN <= 32 6
DAYS MIN <= 0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 5.32 2011
MINIMUM 0.18 2006
TOTALS 0.59 1.92 -1.33 1.14
DAILY AVG. 0.02 0.06 -0.04
DAYS >= .01 5
DAYS >= .10 2
DAYS >= .50 0
DAYS >= 1.00 0
GREATEST
24 HR. TOTAL 0.29 05/21 TO 05/21
STORM TOTAL 0.29
SNOWFALL (INCHES)
TOTALS 0.8 MM MM
SINCE 7/1 16.4 MM MM
SNOWDEPTH AVG. T
DAYS >= 1.0 0
DEGREE DAYS
HEATING TOTAL 302 375 -73
SINCE 7/1 5720 7812 -2092
COOLING TOTAL 23 8 15
SINCE 1/1 23 8 15
..............................................................
WIND (MPH)
AVERAGE WIND SPEED 10.3
RESULTANT WIND SPEED/DIRECTION 3/300
HIGHEST WIND SPEED/DIRECTION 45/260 DATE 05/13
HIGHEST GUST SPEED/DIRECTION 60/250 DATE 05/13
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.21
NUMBER OF DAYS FAIR 25
NUMBER OF DAYS PC 4
NUMBER OF DAYS CLOUDY 2
AVERAGE RH (PERCENT) 45
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 1 MIXED PRECIP 0
HEAVY RAIN 0 RAIN 0
LIGHT RAIN 10 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 0
HEAVY SNOW 0 SNOW 1
LIGHT SNOW 4 SLEET 0
FOG 3 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 JUNE 2026. THE AVERAGE HIGH TEMPERATURE ON THE
FIRST OF THE MONTH IS 73 DEGREES...AND THE AVERAGE LOW TEMPERATURE
IS 45 DEGREES. THE AVERAGE HIGH AT THE END OF THE MONTH IS 84
DEGREES AND THE AVERAGE LOW TEMPERATURE IS 52. THE AVERAGE MONTHLY
PRECIPITATION IS 0.94 INCHES.
$$