Climatological Report (Monthly)
Issued by NWS Sterling, VA

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071
CXUS51 KLWX 021839 RRA
CLMDCA

CLIMATE REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
134 PM EST TUE JAN 2 2018

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

...THE WASHINGTON NATIONAL DC CLIMATE SUMMARY FOR THE MONTH OF DECEMBER 2017...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1871 TO 2018

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE
                                          NORMAL
.............................................................
TEMPERATURE (F)
RECORD
 HIGH              79   12/07/1998
 LOW              -13   12/31/1880
HIGHEST            65   12/23        66      -1
LOWEST             16   12/31        17      -1
                        12/28
AVG. MAXIMUM     46.3              46.8    -0.5     49.2
AVG. MINIMUM     32.1              32.5    -0.4     34.4
MEAN             39.2              39.7    -0.5
DAYS MAX >= 90      0               0.0     0.0
DAYS MAX <= 32      4               1.8     2.2
DAYS MIN <= 32     16              14.5     1.5
DAYS MIN <= 0       0               0.0     0.0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         7.56   1901
 MINIMUM         0.19   1889
TOTALS           0.50              3.05   -2.55     2.61
DAILY AVG.       0.02              0.10   -0.08
DAYS >= .01         6               9.7    -3.7
DAYS >= .10         2               5.6    -3.6
DAYS >= .50         0               2.4    -2.4
DAYS >= 1.00        0               0.5    -0.5
GREATEST
 24 HR. TOTAL    0.18   12/23 TO 12/23

SNOWFALL (INCHES)
RECORDS
 TOTAL           16.6   2009
TOTALS            1.9               2.3    -0.4
SINCE 7/1         1.9               2.8    -0.9
SNOWDEPTH AVG.      0
DAYS >= TRACE       4               1.5     2.5
DAYS >= 1.0         1               0.7     0.3
GREATEST
 SNOW DEPTH         2   12/10
 24 HR TOTAL      1.5

DEGREE_DAYS
HEATING TOTAL     792               786       6      710
 SINCE 7/1       1341              1481    -140     1197
COOLING TOTAL       0                 0       0        0
 SINCE 1/1       1826              1549     277     1994
..............................................................

WIND (MPH)
AVERAGE WIND SPEED              8.2
HIGHEST WIND SPEED/DIRECTION    31/310    DATE  12/25
HIGHEST GUST SPEED/DIRECTION    44/300    DATE  12/25

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.70
NUMBER OF DAYS FAIR            3
NUMBER OF DAYS PC             12
NUMBER OF DAYS CLOUDY         16

AVERAGE RH (PERCENT)     60

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                1     RAIN                       0
LIGHT RAIN                6     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                0     SNOW                       0
LIGHT SNOW                4     SLEET                      0
FOG                       7     FOG W/VIS <= 1/4 MILE      0
HAZE                      2

-  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...

...5TH DRIEST DECEMBER ON RECORD IN WASHINGTON DC...

THE MONTHLY AVERAGE TEMPERATURE WAS 39.2, WHICH IS 0.5 DEGREES BELOW
NORMAL. IT WAS THE COLDEST DECEMBER SINCE 2010, WHEN THE AVERAGE
TEMPERATURE WAS 34.6.

MONTHLY PRECIPITATION WAS 0.50, WHICH IS 2.55 INCHES (84 PERCENT)
BELOW NORMAL. THIS MAKES DECEMBER 2017 THE 5TH DRIEST ON RECORD. IT
WAS THE DRIEST DECEMBER SINCE 1965, WHEN 0.47 INCHES OF
PRECIPITATION FELL.

MONTHLY SNOWFALL WAS 1.9 INCHES, WHICH IS 0.4 INCHES BELOW NORMAL.
IT WAS THE SNOWIEST DECEMBER SINCE 2010, WHEN 2.1 INCHES FELL.

NO DAILY RECORDS WERE SET IN DECEMBER.

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).


$$

RCM



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