474  
CDUS41 KLWX 210529  
CLIIAD  
 
CLIMATE REPORT  
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC  
129 AM EDT TUE SEP 21 2021  
   
...............................
 
 
   
..THE WASHINGTON DULLES DC CLIMATE SUMMARY FOR SEPTEMBER 20 2021
 
 
CLIMATE NORMAL PERIOD: 1991 TO 2020  
CLIMATE RECORD PERIOD: 1960 TO 2021  
 
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST  
VALUE (LST) VALUE VALUE FROM YEAR  
NORMAL    
...............................................................
 
 
TEMPERATURE (F)  
YESTERDAY  
MAXIMUM 79 2:46 PM 91 1965 78 1 68  
MINIMUM 59 2:33 AM 40 1979 56 3 41  
AVERAGE 69 67 2 55  
 
PRECIPITATION (IN)  
YESTERDAY 0.00 0.87 1966 0.14 -0.14 0.00  
MONTH TO DATE 3.04 2.61 0.43 1.48  
SINCE SEP 1 3.04 2.61 0.43 1.48  
SINCE JAN 1 27.63 31.83 -4.20 35.70  
 
SNOWFALL (IN)  
YESTERDAY 0.0 MM MM 0.0 0.0 0.0  
MONTH TO DATE 0.0 0.0 0.0 0.0  
SINCE SEP 1 0.0 0.0 0.0 0.0  
SINCE JUL 1 0.0 0.0 0.0 0.0  
SNOW DEPTH 0  
 
DEGREE DAYS  
HEATING  
YESTERDAY 0 2 -2 10  
MONTH TO DATE 0 14 -14 33  
SINCE SEP 1 0 14 -14 33  
SINCE JUL 1 0 15 -15 33  
 
COOLING  
YESTERDAY 4 4 0 0  
MONTH TO DATE 150 124 26 117  
SINCE SEP 1 150 124 26 117  
SINCE JAN 1 1402 1180 222 1369    
...............................................................
 
 
WIND (MPH)  
HIGHEST WIND SPEED 12 HIGHEST WIND DIRECTION SE (130)  
HIGHEST GUST SPEED 16 HIGHEST GUST DIRECTION SE (120)  
AVERAGE WIND SPEED 4.4  
 
SKY COVER  
AVERAGE SKY COVER 0.6  
 
WEATHER CONDITIONS  
THE FOLLOWING WEATHER WAS RECORDED YESTERDAY.  
NO SIGNIFICANT WEATHER WAS OBSERVED.  
 
RELATIVE HUMIDITY (PERCENT)  
HIGHEST 93 4:00 AM  
LOWEST 50 2:00 PM  
AVERAGE 72  
   
......................................................
 
 
THE WASHINGTON DULLES DC CLIMATE NORMALS FOR TODAY  
NORMAL RECORD YEAR  
MAXIMUM TEMPERATURE (F) 77 92 1965  
1998  
MINIMUM TEMPERATURE (F) 56 33 1962  
 
SUNRISE AND SUNSET  
SEPTEMBER 21 2021.....SUNRISE 6:57 AM EDT SUNSET 7:08 PM EDT  
SEPTEMBER 22 2021.....SUNRISE 6:58 AM EDT SUNSET 7:06 PM EDT  
 
- INDICATES NEGATIVE NUMBERS.  
R INDICATES RECORD WAS SET OR TIED.  
MM INDICATES DATA IS MISSING.  
T INDICATES TRACE AMOUNT.  
 

 
 
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