Climatological Report (Monthly)
Issued by NWS Sterling, VA

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000 CXUS51 KLWX 012130 RRA CLMDCA CLIMATE REPORT NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 530 PM EDT SUN OCT 1 2017 ................................... ...THE WASHINGTON NATIONAL DC CLIMATE SUMMARY FOR THE MONTH OF SEPTEMBER 2017... CLIMATE NORMAL PERIOD 1981 TO 2010 CLIMATE RECORD PERIOD 1871 TO 2017 WEATHER OBSERVED NORMAL DEPART LAST YEAR`S VALUE DATE(S) VALUE FROM VALUE NORMAL ............................................................. TEMPERATURE (F) RECORD HIGH 104 09/07/1881 LOW 36 09/23/1904 HIGHEST 92 09/24 92 0 LOWEST 53 09/10 48 5 AVG. MAXIMUM 80.8 79.5 1.3 MM AVG. MINIMUM 64.2 62.4 1.8 MM MEAN 72.5 71.0 1.5 DAYS MAX >= 90 3 2.4 0.6 DAYS MAX <= 32 0 0.0 0.0 DAYS MIN <= 32 0 0.0 0.0 DAYS MIN <= 0 0 0.0 0.0 PRECIPITATION (INCHES) RECORD MAXIMUM 17.45 1934 MINIMUM 0.11 2005 TOTALS 1.43 3.72 -2.29 MM DAILY AVG. 0.05 0.12 -0.07 DAYS >= .01 4 8.3 -4.3 DAYS >= .10 2 5.5 -3.5 DAYS >= .50 2 2.4 -0.4 DAYS >= 1.00 0 1.0 -1.0 GREATEST 24 HR. TOTAL 0.77 09/02 TO 09/02 DEGREE_DAYS HEATING TOTAL 6 24 -18 MM SINCE 7/1 6 24 -18 MM COOLING TOTAL 241 202 39 MM SINCE 1/1 1732 1513 219 MM .............................................................. WIND (MPH) AVERAGE WIND SPEED 7.5 HIGHEST WIND SPEED/DIRECTION 24/010 DATE 09/30 HIGHEST GUST SPEED/DIRECTION 31/340 DATE 09/30 SKY COVER POSSIBLE SUNSHINE (PERCENT) MM AVERAGE SKY COVER 0.60 NUMBER OF DAYS FAIR 5 NUMBER OF DAYS PC 18 NUMBER OF DAYS CLOUDY 7 AVERAGE RH (PERCENT) 69 WEATHER CONDITIONS. NUMBER OF DAYS WITH THUNDERSTORM 1 MIXED PRECIP 0 HEAVY RAIN 2 RAIN 3 LIGHT RAIN 7 FREEZING RAIN 0 LT FREEZING RAIN 0 HAIL 0 HEAVY SNOW 0 SNOW 0 LIGHT SNOW 0 SLEET 0 FOG 7 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. && WASHINGTON DC...RONALD REAGAN WASHINGTON NATIONAL AIRPORT... THE MONTHLY AVERAGE TEMPERATURE WAS ABOVE NORMAL. MONTHLY PRECIPITATION WAS WELL BELOW NORMAL. THIS WAS THE 8TH STRAIGHT WARMER THAN NORMAL SEPTEMBER. DESPITE THE ABOVE NORMAL MONTHLY AVERAGE TEMPERATURE, THE FIRST THIRD OF THE MONTH RANKED AS THE COOLEST START TO SEPTEMBER SINCE 1986. THE MONTH ENDED WITH 16 CONSECUTIVE DAYS OF NO RAIN (NOT EVEN A TRACE). THIS IS THE 3RD LONGEST STREAK ON RECORD FOR SEPTEMBER. CLIMATE RECORDS HAVE BEEN KEPT AT RONALD REAGAN WASHINGTON NATIONAL AIRPORT SINCE AUGUST OF 1941. ADDITIONAL TEMPERATURE RECORDS FOR THE WASHINGTON DC AREA OBSERVED DOWNTOWN EXTEND BACK TO JANUARY OF 1872. PRECIPITATION RECORDS EXTEND BACK TO JANUARY OF 1871. SNOWFALL RECORDS BEGAN IN JANUARY OF 1884. ALL CLIMATE DATA ARE CONSIDERED PRELIMINARY UNTIL REVIEWED BY THE NATIONAL CENTERS FOR ENVIRONMENTAL INFORMATION (NCEI). $$ DH/HTS

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