388  
CDUS41 KLWX 180521  
CLIIAD  
 
CLIMATE REPORT  
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC  
121 AM EDT SAT SEP 18 2021  
   
...............................
 
 
   
..THE WASHINGTON DULLES DC CLIMATE SUMMARY FOR SEPTEMBER 17 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 82 3:58 PM 97 1991 79 3 72  
MINIMUM 70 11:59 PM 35 1986 58 12 54  
AVERAGE 76 68 8 63  
 
PRECIPITATION (IN)  
YESTERDAY T 1.71 2004 0.14 -0.14 0.18  
MONTH TO DATE 3.04 2.18 0.86 1.34  
SINCE SEP 1 3.04 2.18 0.86 1.34  
SINCE JAN 1 27.63 31.40 -3.77 35.56  
 
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 1 -1 2  
MONTH TO DATE 0 8 -8 13  
SINCE SEP 1 0 8 -8 13  
SINCE JUL 1 0 9 -9 13  
 
COOLING  
YESTERDAY 11 5 6 0  
MONTH TO DATE 128 112 16 116  
SINCE SEP 1 128 112 16 116  
SINCE JAN 1 1380 1168 212 1368    
...............................................................
 
 
WIND (MPH)  
HIGHEST WIND SPEED 13 HIGHEST WIND DIRECTION E (100)  
HIGHEST GUST SPEED 17 HIGHEST GUST DIRECTION E (90)  
AVERAGE WIND SPEED 5.2  
 
SKY COVER  
AVERAGE SKY COVER 0.8  
 
WEATHER CONDITIONS  
THE FOLLOWING WEATHER WAS RECORDED YESTERDAY.  
FOG  
 
RELATIVE HUMIDITY (PERCENT)  
HIGHEST 94 1:00 AM  
LOWEST 65 4:00 PM  
AVERAGE 80  
   
......................................................
 
 
THE WASHINGTON DULLES DC CLIMATE NORMALS FOR TODAY  
NORMAL RECORD YEAR  
MAXIMUM TEMPERATURE (F) 79 91 1978  
MINIMUM TEMPERATURE (F) 57 37 1990  
 
SUNRISE AND SUNSET  
SEPTEMBER 18 2021.....SUNRISE 6:54 AM EDT SUNSET 7:13 PM EDT  
SEPTEMBER 19 2021.....SUNRISE 6:55 AM EDT SUNSET 7:11 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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