181  
CDUS45 KRIW 210731  
CLIP60  
 
CLIMATE REPORT  
NATIONAL WEATHER SERVICE RIVERTON WY  
131 AM MDT SUN SEP 21 2025  
   
...............................  
 
   
..THE LAKE YELLOWSTONE WY CLIMATE SUMMARY FOR SEPTEMBER 20 2025  
 
CLIMATE NORMAL PERIOD: 1991 TO 2020  
CLIMATE RECORD PERIOD: 1998 TO 2025  
 
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST  
VALUE (LST) VALUE VALUE FROM YEAR  
NORMAL    
...............................................................  
 
TEMPERATURE (F)  
YESTERDAY  
MAXIMUM 69R 3:21 PM 69 2012 59 10 58  
2016  
MINIMUM 31 6:34 AM 20 2000 29 2 29  
AVERAGE 50 44 6 44  
 
PRECIPITATION (IN)  
YESTERDAY 0.00 0.60 2019 0.06 -0.06 0.00  
MONTH TO DATE 0.90 1.02 -0.12 1.43  
SINCE SEP 1 0.90 1.02 -0.12 1.43  
SINCE JAN 1 12.61 16.28 -3.67 16.62  
 
DEGREE DAYS  
HEATING  
YESTERDAY 15 21 -6 21  
MONTH TO DATE 286 358 -72 313  
SINCE SEP 1 286 358 -72 313  
SINCE JUL 1 802 1000 -198 890  
 
COOLING  
YESTERDAY 0 0 0 0  
MONTH TO DATE 0 0 0 0  
SINCE SEP 1 0 0 0 0  
SINCE JAN 1 1 0 1 0    
...............................................................  
 
WIND (MPH)  
HIGHEST WIND SPEED 12 HIGHEST WIND DIRECTION W (280)  
HIGHEST GUST SPEED 23 HIGHEST GUST DIRECTION W (280)  
AVERAGE WIND SPEED 1.9  
 
SKY COVER  
POSSIBLE SUNSHINE MM  
AVERAGE SKY COVER 0.0  
 
WEATHER CONDITIONS  
THE FOLLOWING WEATHER WAS RECORDED YESTERDAY.  
NO SIGNIFICANT WEATHER WAS OBSERVED.  
 
RELATIVE HUMIDITY (PERCENT)  
HIGHEST 96 6:00 AM  
LOWEST 20 3:00 PM  
AVERAGE 58  
   
......................................................  
 
THE LAKE YELLOWSTONE WY CLIMATE NORMALS FOR TODAY  
NORMAL RECORD YEAR  
MAXIMUM TEMPERATURE (F) 58 69 2001  
2012  
MINIMUM TEMPERATURE (F) 29 22 2004  
2021  
 
SUNRISE AND SUNSET  
SEPTEMBER 21 2025.....SUNRISE 7:08 AM MDT SUNSET 7:20 PM MDT  
SEPTEMBER 22 2025.....SUNRISE 7:09 AM MDT SUNSET 7:18 PM MDT  
 
- INDICATES NEGATIVE NUMBERS.  
R INDICATES RECORD WAS SET OR TIED.  
MM INDICATES DATA IS MISSING.  
T INDICATES TRACE AMOUNT.  
 
 
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