215

CXUS51 KLWX 020251

CLMIAD



CLIMATE REPORT

NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC                  

951 PM EST SUN NOV 1 2009



................................... 



...THE WASHINGTON DULLES DC CLIMATE SUMMARY FOR THE MONTH OF OCTOBER 2009...



CLIMATE NORMAL PERIOD 1971 TO 2000

CLIMATE RECORD PERIOD 1962 TO 2009



WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR'S         

                 VALUE   DATE(S)  VALUE   FROM    VALUE               

                                          NORMAL                      

.............................................................

TEMPERATURE (F)

RECORD

 HIGH              94   10/09/2007                                    

 LOW               15   10/24/1969                                    

HIGHEST            87   10/09        83       4                       

LOWEST             33   10/19        27       6                       

AVG. MAXIMUM     66.1              67.7    -1.6     66.5              

AVG. MINIMUM     46.6              42.3     4.3     43.8              

MEAN             56.4              55.0     1.4                       

DAYS MAX >= 90      0               0.0     0.0                       

DAYS MAX <= 32      0               0.0     0.0                       

DAYS MIN <= 32      0               4.9    -4.9                       

DAYS MIN <= 0       0               0.0     0.0                       



PRECIPITATION (INCHES)

RECORD

 MAXIMUM         9.22   2005                                          

 MINIMUM            T   1963                                          

TOTALS           5.70              3.37    2.33     1.31              

DAILY AVG.       0.18              0.11    0.07                       

DAYS >= .01        12               7.8     4.2                       

DAYS >= .10         7               5.0     2.0                       

DAYS >= .50         5               2.3     2.7                       

DAYS >= 1.00        2               0.9     1.1                       

GREATEST

 24 HR. TOTAL    1.73   10/23 TO 10/24                                



SNOWFALL (INCHES)

RECORDS

 TOTAL            1.3   1979                                                            TOTALS           0.0               0.1    -0.1                       

TOTALS            0.0               0.1    -0.1 

SINCE 7/1         0.0               0.1    -0.1                       

SNOWDEPTH AVG.      0                                                 

DAYS >= TRACE       0               0.1    -0.1                       

DAYS >= 1.0         0               0.0     0.0                       

GREATEST

 SNOW DEPTH         0   MM                                            

 24 HR TOTAL      0.0                                                 



DEGREE_DAYS

HEATING TOTAL     268               323     -55      314              

 SINCE 7/1        287               388    -101      338              

COOLING TOTAL       8                15      -7       17              

 SINCE 1/1       1259              1072     187     1171              

..............................................................



WIND (MPH)

AVERAGE WIND SPEED              6.8

HIGHEST WIND SPEED/DIRECTION    32/300    DATE  10/07

HIGHEST GUST SPEED/DIRECTION    45/280    DATE  10/07



SKY COVER

POSSIBLE SUNSHINE (PERCENT)   MM                                      



NUMBER OF DAYS FAIR            4

NUMBER OF DAYS PC             11

NUMBER OF DAYS CLOUDY         16



AVERAGE RH (PERCENT)     68



WEATHER CONDITIONS. NUMBER OF DAYS WITH 

THUNDERSTORM              1     MIXED PRECIP               0

HEAVY RAIN                3     RAIN                       7

LIGHT RAIN               17     FREEZING RAIN              0

LT FREEZING RAIN          0     HAIL                       0

HEAVY SNOW                0     SNOW                       0

LIGHT SNOW                0     SLEET                      0

FOG                      15     FOG W/VIS <= 1/4 MILE      1

HAZE                      7                                           

                                                                    

-  INDICATES NEGATIVE NUMBERS.                                      

R  INDICATES RECORD WAS SET OR TIED.                                

MM INDICATES DATA IS MISSING.                                       

T  INDICATES TRACE AMOUNT.                                          



&&



THE AVERAGE MONTHLY TEMPERATURE WAS SLIGHTLY ABOVE NORMAL...MAINLY 

DUE TO THE LOW TEMPERATURE BEING WELL ABOVE NORMAL. A READING OF 87F 

ON THE 9TH TIED FOR THE SECOND WARMEST HIGH TEMPERATURE FOR THAT DAY.



A SLOW MOVING STORM SYSTEM BROUGHT CLOUDY...WET AND VERY COOL 

CONDITIONS DURING THE MIDDLE OF THE MONTH. THE HIGH TEMPERATURE 

FAILED TO REACH 50F DURING A THREE DAY-PERIOD BETWEEN OCTOBER 

15-17...WHICH TIED FOR THE LONGEST STRETCH OF CONSECUTIVE DAYS NOT 

REACHING 50F DURING ANY OCTOBER AT DULLES SINCE 1962.



DULLES HAD ABOVE NORMAL PRECIPITATION THIS MONTH FOR THE FIRST TIME 

SINCE JUNE 2009. IT WAS THE 8TH WETTEST OCTOBER ON RECORD. WETTER 

THAN NORMAL CONDITIONS HAVE OCCURRED SIX OUT OF THE LAST EIGHT 

OCTOBERS. AT LEAST 0.50 INCHES OF PRECIPITATION FELL ON SIX DAYS 

THIS MONTH...WHICH TIED FOR THE MOST OCCURRENCES OF HALF INCH OR 

HIGHER RAINFALL EVENTS FOR ANY OCTOBER SINCE 1976.



RAINFALL OF 1.69 INCHES ON THE 24TH SET A DAILY RECORD FOR THE DATE 

AT DULLES.



$$

JRK/SMZ