676  
CXUS55 KRIW 021724  
CLMP60  
 
CLIMATE REPORT  
NATIONAL WEATHER SERVICE RIVERTON WY  
1111 AM MDT MON JUN 02 2025  
 
...PRELIMINARY MONTHLY CLIMATE SUMMARY FOR LAKE YELLOWSTONE FOR THE  
MONTH OF MAY 2025...  
 
...OFFICIAL CLIMATE DATA FOR THE MONTH OF MAY 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 WARMER AND WETTER THAN NORMAL IN MAY
 
 
AVERAGE TEMPERATURE FOR LAKE YELLOWSTONE IN MAY WAS 41.7 DEGREES  
WHICH IS 3.3 DEGREES ABOVE NORMAL. IT WAS THE 3RD WARMEST MAY SINCE  
RECORDS BEGAN IN 1998. THE WARMEST READING OF THE MONTH WAS 75  
DEGREES ON THE 31ST. THIS BROKE THE 2002 RECORD OF 71 DEGREES. THE  
10TH HIGH OF 68 BROKE THE 2007 RECORD OF 63. THE COLDEST READING OF  
THE MONTH WAS 19 DEGREES ON THE 2ND.  
 
TOTAL PRECIPITATION AT LAKE YELLOWSTONE WAS 2.45 INCHES...WHICH WAS  
104 PERCENT OF NORMAL. THE WETTEST 24-HOUR PERIOD DURING THE MONTH  
WAS THE 18TH-19TH WHEN 0.83 INCHES OF PRECIPITATION FELL. THE 18TH  
HAD 0.82 INCHES AND BROKE THE 2013 RECORD OF 0.46. THE HIGHEST WIND  
GUST WAS 31 MPH FROM THE SOUTHWEST ON THE 11TH.  
 
...THE LAKE YELLOWSTONE WY CLIMATE SUMMARY FOR THE MONTH OF MAY  
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 78 05/28/2003  
LOW 0 05/07/2010  
HIGHEST 75 05/31  
LOWEST 19 05/02  
AVG. MAXIMUM 55.2 50.6 4.6  
AVG. MINIMUM 28.2 26.3 1.9  
MEAN 41.7 38.4 3.3  
DAYS MAX >= 90 0  
DAYS MAX <= 32 0  
DAYS MIN <= 32 30  
DAYS MIN <= 0 0  
 
PRECIPITATION (INCHES)  
RECORD  
MAXIMUM 4.53 2022  
MINIMUM 0.42 2019  
TOTALS 2.45 2.35 0.10 2.40  
DAILY AVG. 0.08 0.08 0.00  
DAYS >= .01 15  
DAYS >= .10 7  
DAYS >= .50 1  
DAYS >= 1.00 0  
GREATEST  
24 HR. TOTAL 0.83 05/18 TO 05/19  
STORM TOTAL 0.82  
 
DEGREE DAYS  
HEATING TOTAL 717 823 -106  
SINCE 7/1 8832 11473 -2641  
COOLING TOTAL 0 0 0  
SINCE 1/1 0 0 0    
..........................................................
 
 
WIND (MPH)  
AVERAGE WIND SPEED 1.9  
RESULTANT WIND SPEED/DIRECTION 0/090  
HIGHEST WIND SPEED/DIRECTION 14/280 DATE 05/29  
14/260 05/27  
14/270 05/15  
HIGHEST GUST SPEED/DIRECTION 31/240 DATE 05/11  
 
SKY COVER  
POSSIBLE SUNSHINE (PERCENT) MM  
AVERAGE SKY COVER 0.00  
NUMBER OF DAYS FAIR 18  
NUMBER OF DAYS PC 0  
NUMBER OF DAYS CLOUDY 0  
 
AVERAGE RH (PERCENT) 69  
 
WEATHER CONDITIONS. NUMBER OF DAYS WITH  
THUNDERSTORM 0 MIXED PRECIP 0  
HEAVY RAIN 0 RAIN 0  
LIGHT RAIN 15 FREEZING RAIN 0  
LT FREEZING RAIN 0 HAIL 0  
HEAVY SNOW 0 SNOW 0  
LIGHT SNOW 5 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 JUNE 2025. THE AVERAGE HIGH TEMPERATURE ON THE  
FIRST OF THE MONTH IS 56 DEGREES...AND THE AVERAGE LOW TEMPERATURE  
IS 31 DEGREES. THE AVERAGE HIGH BY THE END OF THE MONTH IS 68  
DEGREES AND THE AVERAGE LOW TEMPERATURE IS 36 DEGREES. THE AVERAGE  
MONTHLY PRECIPITATION IS 2.38 INCHES.  
 

 
 
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