000 CXUS51 KLWX 031838 CLMIAD CLIMATE REPORT NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 138 PM EST WED FEB 3 2010 ................................... ...THE WASHINGTON DULLES DC CLIMATE SUMMARY FOR THE MONTH OF JANUARY 2010... CLIMATE NORMAL PERIOD 1971 TO 2000 CLIMATE RECORD PERIOD 1962 TO 2010 WEATHER OBSERVED NORMAL DEPART LAST YEAR'S VALUE DATE(S) VALUE FROM VALUE NORMAL ............................................................. TEMPERATURE (F) RECORD HIGH 75 01/29/1975 LOW -18 01/22/1984 HIGHEST 65 01/25 63 2 LOWEST 11 01/31 2 9 AVG. MAXIMUM 41.5 41.4 0.1 38.0 AVG. MINIMUM 25.3 21.9 3.4 21.2 MEAN 33.4 31.7 1.7 DAYS MAX >= 90 0 0.0 0.0 DAYS MAX <= 32 7 6.4 0.6 DAYS MIN <= 32 25 25.6 -0.6 DAYS MIN <= 0 0 1.1 -1.1 PRECIPITATION (INCHES) RECORD MAXIMUM 6.61 1979 MINIMUM 0.40 1981 TOTALS 2.01 3.05 -1.04 2.64 DAILY AVG. 0.06 0.10 -0.04 DAYS >= .01 9 10.7 -1.7 DAYS >= .10 6 6.2 -0.2 DAYS >= .50 1 2.1 -1.1 DAYS >= 1.00 0 0.6 -0.6 GREATEST 24 HR. TOTAL 0.63 01/17 TO 01/17 01/16 TO 01/17 01/17 TO 01/17 SNOWFALL (INCHES) RECORDS TOTAL 30.9 1996 TOTALS 5.7 8.1 -2.4 SINCE 7/1 27.1 11.2 15.9 SNOWDEPTH AVG. 0 DAYS >= TRACE 6 3.8 2.2 DAYS >= 1.0 2 2.1 -0.1 GREATEST SNOW DEPTH 5 01/31 24 HR TOTAL 4.5 DEGREE_DAYS HEATING TOTAL 973 1025 -52 1089 SINCE 7/1 2624 2886 -262 2862 COOLING TOTAL 0 0 0 0 SINCE 1/1 0 0 0 0 .............................................................. WIND (MPH) AVERAGE WIND SPEED 9.5 HIGHEST WIND SPEED/DIRECTION 38/300 DATE 01/03 HIGHEST GUST SPEED/DIRECTION 49/140 DATE 01/25 SKY COVER POSSIBLE SUNSHINE (PERCENT) MM NUMBER OF DAYS FAIR 6 NUMBER OF DAYS PC 13 NUMBER OF DAYS CLOUDY 12 AVERAGE RH (PERCENT) 59 WEATHER CONDITIONS. NUMBER OF DAYS WITH THUNDERSTORM 0 MIXED PRECIP 0 HEAVY RAIN 1 RAIN 4 LIGHT RAIN 6 FREEZING RAIN 0 LT FREEZING RAIN 0 HAIL 0 HEAVY SNOW 0 SNOW 2 LIGHT SNOW 4 SLEET 2 FOG 11 FOG W/VIS <= 1/4 MILE 2 HAZE 4 - INDICATES NEGATIVE NUMBERS. R INDICATES RECORD WAS SET OR TIED. MM INDICATES DATA IS MISSING. T INDICATES TRACE AMOUNT. && AT DULLES...ALTHOUGH THE MONTHLY AVERAGE TEMPERATURE FOR JANUARY ENDED UP BEING NEAR NORMAL...IT WAS A MONTH SPLIT BETWEEN COLD AND WARM PERIODS. IT WAS COLD DURING MOST OF THE FIRST TWO WEEKS OF THE MONTH...9 OUT OF THE FIRST 12 DAYS WERE BELOW NORMAL. THIS COLD PERIOD WAS FOLLOWED BY TWO WEEKS OF ABOVE NORMAL TEMPERATURES FROM THE 13TH THROUGH 28TH...FOLLOWED BY SHARPLY COLDER CONDITIONS TO FINISH OUT THE MONTH. PRECIPITATION THIS JANUARY WAS BELOW NORMAL...WHICH MAKES IT THE FIFTH JANUARY IN A ROW AND 10 OUT OF THE LAST 11 WITH BELOW NORMAL PRECIPITATION. SNOWFALL WAS BELOW NORMAL FOR THE MONTH. IT WAS THE 10TH CONSECUTIVE JANUARY WITH BELOW NORMAL SNOWFALL. DESPITE THE BELOW NORMAL SNOWFALL...THE TWO-MONTH TOTAL OF 27.1 INCHES OF SNOW MEASURED AT DULLES DURING THE PAST DEC-JAN PERIOD MARKS THE THIRD SNOWIEST DEC-JAN PERIOD ON RECORD...ONLY 1986-87 AND 1995-96 HAD HIGHER TWO MONTH DEC-JAN SNOW TOTALS. $$ JRK/SMZ