557  
CXUS55 KRIW 021721  
CLMCPR  
 
CLIMATE REPORT  
NATIONAL WEATHER SERVICE RIVERTON WY  
1111 AM MDT MON JUN 02 2025  
 
...PRELIMINARY MONTHLY CLIMATE SUMMARY FOR CASPER FOR THE MONTH OF  
MAY 2025...  
 
...OFFICIAL CLIMATE DATA FOR THE MONTH OF MAY 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  
   
..MAY WAS WARMER AND DRIER THAN NORMAL FOR CASPER
 
 
AVERAGE TEMPERATURE FOR CASPER IN MAY WAS 53 DEGREES WHICH IS 1  
DEGREE ABOVE NORMAL. THE WARMEST READING OF THE MONTH WAS 84 DEGREES  
ON THE 12TH. THE COLDEST READING FOR THE MONTH WAS 28 DEGREES ON THE  
22ND. NO TEMPERATURE RECORDS WERE BROKEN THIS MONTH.  
 
TOTAL PRECIPITATION FOR THE MONTH WAS 1.28 INCHES...WHICH IS 58  
PERCENT OF NORMAL. THE WETTEST 24-HOUR PERIOD DURING THE MONTH WAS  
ON THE 18TH-19TH WITH 0.31 INCHES. NO PRECIPITATION RECORDS WERE  
BROKEN THIS MONTH.  
 
SNOWFALL FOR THE MONTH WAS 0.3 INCHES...WHICH IS 12 PERCENT OF  
NORMAL THE SNOWIEST 24-HOUR PERIOD WAS THE 6TH WITH 0.3 INCHES.  
THERE WERE NO SNOWFALL RECORDS BROKEN THIS MONTH. THE HIGHEST WIND  
GUST WAS 56 MPH FROM THE SOUTHEAST ON THE 4TH.  
   
..THE CASPER WY CLIMATE SUMMARY FOR THE MONTH OF MAY 2025
 
 
CLIMATE NORMAL PERIOD: 1991 TO 2020  
CLIMATE RECORD PERIOD: 1939 TO 2025  
 
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S  
VALUE DATE(S) VALUE FROM VALUE  
NORMAL    
..........................................................
 
 
TEMPERATURE (F)  
RECORD  
HIGH 95 05/29/2003  
LOW 16 05/12/1953  
HIGHEST 84 05/12  
LOWEST 28 05/22  
AVG. MAXIMUM 67.8 66.8 1.0  
AVG. MINIMUM 38.3 37.1 1.2  
MEAN 53.0 52.0 1.0  
DAYS MAX >= 90 0  
DAYS MAX <= 32 0  
DAYS MIN <= 32 7  
DAYS MIN <= 0 0  
 
PRECIPITATION (INCHES)  
RECORD  
MAXIMUM 6.46 1978  
MINIMUM 0.30 2020  
TOTALS 1.28 2.21 -0.93 2.44  
DAILY AVG. 0.04 0.07 -0.03  
DAYS >= .01 11  
DAYS >= .10 5  
DAYS >= .50 0  
DAYS >= 1.00 0  
GREATEST  
24 HR. TOTAL 0.31 05/18 TO 05/19  
STORM TOTAL 0.26  
 
SNOWFALL (INCHES)  
TOTALS 0.3 2.6 -2.3  
SINCE 7/1 26.5 71.7 -45.2  
SNOWDEPTH AVG. T  
DAYS >= 1.0 0  
 
DEGREE DAYS  
HEATING TOTAL 367 409 -42  
SINCE 7/1 6931 7361 -430  
COOLING TOTAL 0 4 -4  
SINCE 1/1 0 4 -4    
..........................................................
 
 
WIND (MPH)  
AVERAGE WIND SPEED 9.7  
RESULTANT WIND SPEED/DIRECTION 1/310  
HIGHEST WIND SPEED/DIRECTION 39/140 DATE 05/04  
HIGHEST GUST SPEED/DIRECTION 56/130 DATE 05/04  
 
SKY COVER  
POSSIBLE SUNSHINE (PERCENT) MM  
AVERAGE SKY COVER 0.33  
NUMBER OF DAYS FAIR 18  
NUMBER OF DAYS PC 8  
NUMBER OF DAYS CLOUDY 3  
 
AVERAGE RH (PERCENT) 61  
 
WEATHER CONDITIONS. NUMBER OF DAYS WITH  
THUNDERSTORM 6 MIXED PRECIP 0  
HEAVY RAIN 1 RAIN 0  
LIGHT RAIN 14 FREEZING RAIN 0  
LT FREEZING RAIN 0 HAIL 0  
HEAVY SNOW 0 SNOW 0  
LIGHT SNOW 2 SLEET 0  
FOG 8 FOG W/VIS <= 1/4 MILE 2  
HAZE 2  
 
- INDICATES NEGATIVE NUMBERS.  
R INDICATES RECORD WAS SET OR TIED.  
MM INDICATES DATA IS MISSING.  
T INDICATES TRACE AMOUNT.  
 
LOOKING AHEAD TO JUNE 2025. THE AVERAGE HIGH TEMPERATURE ON THE  
FIRST OF THE MONTH IS 74 DEGREES...AND THE AVERAGE LOW TEMPERATURE  
IS 42 DEGREES. THE AVERAGE HIGH BY THE END OF THE MONTH IS 85  
DEGREES...AND THE AVERAGE LOW TEMPERATURE IS 49. THE AVERAGE MONTHLY  
PRECIPITATION IS 1.34 INCHES. THE AVERAGE SNOWFALL IS 0.1 INCHES.  
 

 
 
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