2001 WASHINGTON, D.C. RONALD REAGAN NATIONAL AIRPORT (DCA)



Washington lies at the western edge of the mid Atlantic Coastal Plain, about 50 miles east of the Blue Ridge Mountains and 35 miles west of Chesapeake Bay, adjacent to the Potomac and Anacostia Rivers. Elevations range from a few feet above sea level to about 400 feet in parts of the northwest section of the city.

Observations have been kept continuously since November 1870. Since June 1941 the official observations have been taken at Washington National Airport.

National Airport is located at the center of the urban heat island. As a result, low temperatures are the highest for the area. Differences between the airport and suburban locations are often 10 to 15 degrees. There is less variation in the high temperatures.

Summers are warm and humid and winters are cold, but not severe. Periods of pleasant weather often occur in the spring and fall. The summertime temperature is in the upper 80s and the winter is in the upper 20s. Precipitation is rather uniformly distributed throughout the year.

Thunderstorms can occur at any time but are most frequent during the late spring and summer. The storms are most often accompanied by downpours and gusty winds, but are not usually severe.

Tornadoes, which infrequently occur, have resulted in significant damage. Severe hailstorms have occurred in the spring.

Tropical storms can bring heavy rain, high winds and flooding, but extensive damage from wind and tidal flooding is rare. Wind gusts of nearly 100 mph and rainfall over 7 inches have occurred during the passage of tropical storms and hurricanes.

Major flooding of the Potomac River can result from heavy rains over the basin, occasionally augmented by snowmelt, and above normal tides associated with hurricanes or severe storms along the coast. Flooding may also occur after a cold winter when the Potomac may be blocked with ice.

Although a snowfall of 10 inches or more in 24 hours is unusual, several notable falls of more than 25 inches have occurred. Normal snowfall during the winter season is 18 inches.

The average date of the last freezing temperature in the spring is April 1 and the average date for the first freezing temperature in the fall is November 10.

NORMALS, MEANS, AND EXTREMES

WASHINGTON DC, DC (DCA)

LATITUDE:    LONGITUDE:     ELEVATION (FT):    TIME ZONE:    WBAN: 13743

38 51′ 54″ N  77 02′ 03″ W;  GRND:  10  BARO: � A0;3  EASTERN  (UTC + 5)

2001 Washington, D.C. Ronald Reagan National Airport (DCA)

ELEMENT POR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC YEAR
TEMPERATURE F NORMAL DAILY MAXIMUM 30 42.3 45.9 56.5 66.7 76.2 84.7 88.5 86.9 80.1 69.1 58.3 47.0 66.8
MEAN DAILY MAXIMUM 56 43.4 46.8 55.3 66.6 75.7 83.9 87.9 86.1 79.6 68.9 57.6 46.8 66.5
HIGHEST DAILY MAXIMUM 60 79 82 89 95 99 101 104 105 101 94 86 79 105
YEAR OF OCCURRENCE 1950 1948 1990 1976 1991 1994 1988 1997 1980 1954 1974 1998 AUG 1997
MEAN OF EXTREME MAXS. 56 64.5 67.4 77.5 85.7 90.3 95.3 96.8 95.5 92.3 83.8 75.3 66.3 82.6
NORMAL DAILY MINIMUM 30 26.8 29.1 37.7 46.4 56.6 66.5 71.4 70.0 62.5 50.3 41.1 31.7 49.2
MEAN DAILY MINIMUM 56 28.2 30.0 37.0 46.3 56.2 65.4 70.2 68.8 62.0 50.2 40.4 31.8 48.9
LOWEST DAILY MINIMUM 60 -5 4 11 24 34 47 54 49 39 29 16 1 -5
YEAR OF OCCURRENCE 1982 1961 1943 1982 1947 1972 1988 1986 1963 1969 1955 1942 JAN 1982
MEAN OF EXTREME MINS. 56 12.3 15.3 22.9 33.2 43.7 53.5 60.8 58.6 48.3 36.6 26.8 17.4 35.8
NORMAL DRY BULB 30 34.6 37.5 47.2 56.5 66.4 75.6 80.0 78.5 71.3 59.7 49.8 39.4 58.0
MEAN DRY BULB 56 35.7 38.4 46.2 56.5 65.9 74.7 79.1 77.4 70.7 59.6 49.0 39.3 57.7
MEAN WET BULB 18 32.2 34.8 40.2 49.5 58.9 67.4 71.2 70.2 63.9 53.7 43.7 35.5 51.8
MEAN DEW POINT 18 24.7 27.1 31.6 41.9 53.3 62.7 66.9 66.1 59.7 48.4 37.3 28.5 45.7
NORMAL NO. DAYS WITH:
MAXIMUM 90 30 0.0 0.0 0.0 0.4 1.5 7.4 13.8 10.1 3.9 0.1 0.0 0.0 37.2
MAXIMUM 32 30 5.2 2.3 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 * 2.1 9.8
MINIMUM 32 30 22.3 18.5 8.4 0.9 0.0 0.0 0.0 0.0 0.0 0.4 4.2 15.7 70.4
MINIMUM 0 30 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1
H/C NORMAL HEATING DEG. DAYS 30 942 770 552 264 60 0 0 0 14 195 456 794 4047
NORMAL COOLING DEG. DAYS 30 0 0 0 9 104 318 465 419 203 31 0 0 1549
RH NORMAL (PERCENT) 30 62 60 59 58 64 66 67 69 70 67 65 64 64
HOUR 01 LST 30 66 66 64 66 74 76 77 79 79 76 71 68 72
HOUR 07 LST 30 69 69 70 69 74 75 76 80 81 79 75 71 74
HOUR 13 LST 30 55 52 49 48 52 52 53 55 55 53 54 56 53
HOUR 19 LST 30 59 56 53 51 59 60 61 64 66 64 61 61 60
S PERCENT POSSIBLE SUNSHINE 50 46 50 55 57 58 64 62 62 61 59 51 46 56
W/O MEAN NO. DAYS WITH:
HEAVY FOG (VISBY1/4 MI) 53 1.7 1.5 0.9 0.8 0.4 0.2 0.1 0.1 0.3 1.3 1.3 1.7 10.3
THUNDERSTORMS 53 0.2 0.2 1.2 2.6 4.6 5.9 6.6 5.2 2.4 1.1 0.6 0.0 30.6
CLOUDINESS MEAN:
SUNRISE-SUNSET (OKTAS) 49 5.4 5.2 5.2 5.1 5.1 4.8 4.8 4.6 4.6 4.3 5.0 5.2 4.9
MIDNIGHT-MIDNIGHT (OKTAS) 33 5.1 5.0 5.0 4.8 5.0 4.7 4.8 4.5 4.5 4.2 4.7 5.1 4.8
MEAN NO. DAYS WITH:
CLEAR 50 7.2 7.0 7.5 7.1 6.9 7.3 7.4 8.6 9.4 10.7 7.7 7.9 94.7
PARTLY CLOUDY 50 7.4 6.7 8.3 9.1 10.1 11.4 11.8 10.2 8.4 7.9 7.8 6.6 105.7
CLOUDY 50 16.4 14.5 15.2 13.9 14.0 11.4 11.4 11.7 11.6 11.9 13.8 15.9 161.7
PR MEAN STATION PRESSURE (IN) 29 30.03 30.02 29.97 29.92 29.92 29.92 29.94 29.98 30.01 30.04 30.03 30.05 29.99
MEAN SEA-LEVEL PRES. (IN) 18 30.11 30.11 30.05 29.99 29.99 29.98 30.00 30.03 30.07 30.11 30.13 30.13 30.06
WINDS MEAN SPEED (MPH) 54 10.2 10.7 11.1 10.7 9.6 9.0 8.5 8.3 8.5 8.8 9.5 9.6 9.5
PREVAIL. DIR (TENS OF DEGS) 32 32 32 32 18 18 18 18 18 18 18 18 33 18
MAXIMUM 2-MINUTE:
SPEED (MPH) 3 41 36 37 39 37 49 47 33 39 32 34 34 49
DIR. (TENS OF DEGS) 29 28 28 31 26 31 05 31 32 35 16 32 31
YEAR OF OCCURRENCE 2000 2001 2001 2000 1999 1999 2000 2000 2000 1999 1999 1999 JUN 1999
MAXIMUM 5-SECOND:
SPEED (MPH) 3 55 51 48 51 55 60 53 45 55 41 44 45 60
DIR. (TENS OF DEGS) 31 27 29 31 25 31 05 35 32 36 16 28 31
YEAR OF OCCURRENCE 2000 2001 2001 2000 2000 1999 2000 2000 1999 1999 1999 2000 JUN 1999
PRECIPITATION NORMAL (IN) 30 2.72 2.71 3.17 2.71 3.66 3.38 3.80 3.91 3.31 3.02 3.12 3.12 38.63
MAXIMUM MONTHLY (IN) 60 7.11 5.71 8.45 6.88 10.69 11.53 11.06 14.31 12.36 8.65 6.70 6.54 14.31
YEAR OF OCCURRENCE 1978 1961 1994 1983 1953 1972 1945 1955 1975 1995 1963 1969 AUG 1955
MINIMUM MONTHLY (IN) 60 0.31 0.42 0.64 0.03 0.75 0.95 0.93 0.55 0.20 T 0.29 0.22 T
YEAR OF OCCURRENCE 1955 1978 1945 1985 1986 1988 1966 1962 1967 1963 1981 1955 OCT 1963
MAXIMUM IN 24 HOURS (IN) 58 2.13 2.13 3.43 3.08 4.32 7.19 4.69 6.39 5.31 4.98 4.03 2.86 7.19
YEAR OF OCCURRENCE 1976 1998 1958 1970 1953 1972 1970 1955 1975 1955 1993 1977 JUN 1972
NORMAL NO. DAYS WITH:
PRECIPITATION 0.01 30 9.8 9.5 10.1 9.6 10.8 9.7 9.6 8.9 7.2 7.2 8.5 8.9 109.8
PRECIPITATION 1.00 30 0.4 0.5 0.6 0.4 0.9 0.8 1.0 1.3 1.0 1.0 0.8 0.7 9.4
SNOWFALL NORMAL (IN) 30 6.2 6.3 1.6 0.* 0.0 0.0 0.0 0.0 0.0 0.* 1.0 3.1 18.2
MAXIMUM MONTHLY (IN) 58 23.8 30.6 17.1 0.6 T T T T 0.0 0.3 11.5 16.2 30.6
YEAR OF OCCURRENCE 1996 1979 1960 1972 1993 1998 1990 1996 1979 1987 1962 FEB 1979
MAXIMUM IN 24 HOURS (IN) 58 13.8 18.7 8.4 0.6 T T T T 0.0 0.3 11.5 11.4 18.7
YEAR OF OCCURRENCE 1966 1979 1999 1972 1993 1998 1990 1992 1979 1987 1957 FEB 1979
MAXIMUM SNOW DEPTH (IN) 55 18 22 8 1 0 0 0 0 0 0 12 8 22
YEAR OF OCCURRENCE 1987 1979 1960 1972 1987 1973 FEB 1979
NORMAL NO. DAYS WITH:
SNOWFALL 1.0 30 1.6 1.5 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.7 4.5

2001 Washington, D.C. Ronald Reagan National Airport (DCA)

PRECIPITATION (inches) 2001 WASHINGTON, D.C. DC (DCA)
YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
1972 2.45 5.27 2.27 3.99 4.78 11.53 3.43 2.82 1.27 3.56 6.05 4.55 51.97
1973 2.26 2.68 2.97 4.19 3.39 2.11 2.68 4.41 1.58 1.71 0.97 6.03 34.98
1974 2.66 0.95 4.21 2.26 4.37 3.40 1.15 5.77 4.39 1.13 1.24 4.43 35.96
1975 3.09 1.56 5.33 2.13 4.71 2.15 7.16 3.54 12.36 2.38 2.05 4.04 50.50
1976 3.56 1.55 2.51 1.17 3.57 1.21 4.54 2.13 7.23 7.76 0.85 1.99 38.07
1977 1.50 0.66 2.17 2.66 1.73 3.28 4.06 4.74 0.32 5.35 4.81 4.86 36.14
1978 7.11 0.42 4.48 1.38 5.13 2.43 4.28 5.85 1.01 1.16 2.31 4.00 39.56
1979 6.64 5.62 2.45 1.88 3.55 2.99 3.43 5.41 6.64 5.54 2.33 0.85 47.33
1980 2.85 1.16 5.04 3.28 2.64 1.68 3.86 1.11 1.90 2.59 2.56 0.65 29.32
1981 0.38 2.82 1.49 2.63 3.42 2.55 5.69 3.02 1.94 3.64 0.29 2.80 30.67
1982 2.27 3.33 2.64 3.19 5.11 5.41 2.98 2.68 1.71 1.75 2.96 1.74 35.77
1983 1.69 3.09 4.84 6.88 4.62 7.09 1.78 3.11 2.90 4.87 5.09 5.91 51.87
1984 1.71 3.43 6.14 3.71 3.80 2.01 4.09 2.30 2.51 3.18 3.66 1.19 37.73
1985 2.11 3.07 1.88 0.03 5.79 2.05 2.91 2.35 6.67 3.85 4.47 0.68 35.86
1986 2.38 3.49 0.74 1.98 0.75 1.29 3.79 5.33 0.60 2.01 5.23 4.98 32.57
1987 4.90 2.11 1.54 2.28 2.54 3.90 2.59 2.07 5.11 2.53 4.49 2.57 36.63
1988 3.14 2.52 2.27 2.00 4.50 0.95 3.74 2.39 1.85 1.75 5.33 1.30 31.74
1989 2.49 2.80 4.30 3.50 7.77 6.02 5.66 1.15 6.68 5.48 2.37 2.10 50.32
1990 2.95 1.30 2.57 4.09 5.20 3.14 3.78 6.74 0.87 3.30 2.17 4.73 40.84
1991 2.90 0.83 4.42 1.39 1.57 1.27 3.76 2.03 3.50 2.03 0.85 5.07 29.62
1992 2.78 2.23 3.48 2.55 3.41 2.35 5.34 2.48 3.49 2.03 3.38 2.86 36.38
1993 2.90 2.27 6.82 3.62 3.40 1.73 1.36 3.87 3.68 2.62 4.76 4.38 41.41
1994 4.28 4.20 8.45 1.58 1.56 1.59 3.61 4.35 2.84 1.19 1.57 2.35 37.57
1995 3.22 1.71 2.14 1.89 4.19 2.42 4.03 0.88 3.73 8.65 4.77 2.17 39.80
1996 5.01 1.99 3.60 3.17 4.96 3.14 5.60 2.63 7.79 4.04 3.58 5.51 51.02
1997 2.55 2.43 4.15 2.41 3.04 2.94 1.14 3.51 1.59 3.72 4.60 1.74 33.82
1998 5.43 5.23 5.40 3.96 4.05 4.42 1.79 0.59 1.83 0.59 0.91 1.74 35.94
1999 5.42 2.54 3.87 2.09 1.28 2.26 1.01 5.02 10.27 2.16 1.82 2.49 40.23
2000 3.66 2.06 3.98 5.13 3.08 4.93 5.51 3.77 4.91 0.02 1.60 2.01 40.66
2001 2.22 1.83 3.88 1.68 3.71 4.69 4.78 2.98 1.41 0.69 0.55 1.53 29.95
POR=60 YRS 2.90 2.56 3.49 2.81 3.80 3.30 3.84 4.01 3.43 2.90 2.92 2.96 38.92

2001 Washington, D.C. Ronald Reagan National Airport (DCA)

AVERAGE TEMPERATURE (F) 2001 WASHINGTON, D.C. DC (DCA)
YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
1972 38.5 36.5 45.6 54.1 64.6 70.2 77.5 75.9 71.0 56.0 46.8 43.6 56.7
1973 37.6 37.0 51.1 56.0 62.8 77.1 79.2 79.9 74.3 63.3 51.6 41.9 59.3
1974 42.9 39.2 49.2 58.3 65.1 71.5 79.0 78.4 70.2 57.3 50.9 43.1 58.8
1975 40.9 40.6 45.2 53.6 69.7 76.4 79.3 80.1 68.5 63.2 54.4 40.5 59.4
1976 33.9 46.9 51.3 59.9 65.0 77.6 78.4 76.7 70.4 55.4 43.0 35.5 57.8
1977 25.4 38.8 52.7 60.1 69.4 74.3 80.9 78.8 73.9 59.0 51.8 38.1 58.6
1978 32.5 31.4 44.4 57.7 65.8 76.7 78.8 81.3 73.6 59.4 52.2 43.1 58.1
1979 35.1 28.4 51.5 56.0 67.7 72.4 78.6 78.5 71.6 58.6 54.4 43.7 58.0
1980 37.2 36.1 46.2 60.1 69.5 74.8 82.3 82.8 77.1 59.9 48.6 39.8 59.5
1981 33.0 43.7 47.6 62.1 66.2 78.7 80.2 77.0 71.0 58.3 51.4 38.5 59.0
1982 28.1 38.3 45.7 54.0 69.0 72.8 80.3 75.4 70.6 60.2 51.8 45.5 57.6
1983 38.1 38.7 48.8 53.3 64.9 75.0 81.2 81.0 72.6 60.5 50.3 36.0 58.4
1984 32.2 43.8 41.8 54.9 64.9 76.9 76.5 77.8 68.3 65.2 46.0 45.6 57.8
1985 30.8 37.8 47.7 61.6 68.1 72.3 79.0 76.7 71.9 61.2 54.3 36.4 58.2
1986 35.4 35.3 47.4 56.2 68.1 76.6 81.1 74.6 70.9 61.1 46.5 39.8 57.8
1987 34.7 37.0 47.7 54.8 67.2 76.4 82.6 78.7 72.1 54.4 49.9 41.5 58.1
1988 31.0 37.3 47.2 54.4 65.8 74.4 81.9 80.7 68.9 54.4 49.9 38.7 57.1
1989 39.9 37.8 46.1 55.4 64.1 76.8 78.3 77.1 71.4 60.5 48.0 27.9 56.9
1990 43.6 45.2 50.2 56.8 64.3 75.0 79.4 76.5 69.6 62.8 52.0 44.5 60.0
1991 38.6 43.0 48.8 58.2 73.0 76.8 81.4 80.0 71.0 60.4 48.8 42.3 60.2
1992 38.2 41.2 45.0 55.4 62.3 71.7 79.5 74.0 69.2 56.0 48.8 39.6 56.7
1993 39.7 34.3 42.2 54.8 67.4 75.3 83.1 79.6 71.0 58.1 48.8 38.1 57.7
1994 28.8 36.3 45.4 62.0 63.1 79.4 81.8 75.5 70.2 59.1 53.4 44.2 58.3
1995 39.6 34.4 49.2 56.3 65.8 74.6 81.5 81.3 71.0 62.3 43.1 35.6 57.9
1996 32.9 37.3 42.9 56.8 63.9 77.2 77.6 76.5 70.6 59.4 44.1 43.0 56.9
1997 37.0 44.7 48.7 54.0 62.9 73.1 80.4 77.6 70.5 59.6 46.2 41.0 58.0
1998 43.0 43.4 46.9 57.4 67.5 73.0 78.9 79.4 75.4 60.1 50.3 44.4 60.0
1999 38.2 41.0 44.5 56.5 67.3 74.7 83.0 79.7 70.0 57.2 53.1 42.0 58.9
2000 35.9 42.5 51.7 55.6 67.8 74.7 74.7 75.1 67.6 60.2 46.7 31.8 57.0
2001 35.5 40.9 43.8 57.6 65.9 75.2 75.3 78.9 68.9 59.7 54.8 45.5 58.5
POR=60 YRS 35.7 38.3 46.3 56.4 66.0 74.7 79.0 77.3 70.7 59.5 49.0 39.1 57.7

REFERENCE NOTES:

PAGE 1:

THE TEMPERATURE GRAPH SHOWS NORMAL MAXIMUM AND NORMAL MINIMUM DAILY TEMPERATURES (SOLID CURVES) AND THE ACTUAL DAILY HIGH AND LOW TEMPERATURES (VERTICAL BARS).

PAGE 2 AND 3:

H/C INDICATES HEATING AND COOLING DEGREE DAYS.

RH INDICATES RELATIVE HUMIDITY

W/O INDICATES WEATHER AND OBSTRUCTIONS

S INDICATES SUNSHINE.

PR INDICATES PRESSURE.

CLOUDINESS ON PAGE 3 IS THE SUM OF THE CEILOMETER AND SATELLITE DATA NOT TO EXCEED EIGHT EIGHTHS (OKTAS).

GENERAL:

T INDICATES TRACE PRECIPITATION, AN AMOUNT GREATER THAN ZERO BUT LESS THAN THE LOWEST REPORTABLE VALUE.

+ INDICATES THE VALUE ALSO OCCURS ON EARLIER DATES.

BLANK ENTRIES DENOTE MISSING OR UNREPORTED DATA.

NORMALS ARE 30–YEAR AVERAGES (1961–1990).

ASOS INDICATES AUTOMATED SURFACE OBSERVING SYSTEM.

PM INDICATES THE LAST DAY OF THE PREVIOUS MONTH.

POR (PERIOD OF RECORD) BEGINS WITH THE JANUARY DATA MONTH AND IS THE NUMBER OF YEARS USED TO COMPUTE THE MEAN. INDIVIDUAL MONTHS WITHIN THE POR MAY BE MISSING.

WHEN THE POR FOR A NORMAL IS LESS THAN 30 YEARS, THE NORMAL IS PROVISIONAL AND IS BASED ON THE NUMBER OF YEARS INDICATED.

0.* OR * INDICATES THE VALUE OR MEAN–DAYS–WITH IS BETWEEN 0.00 AND 0.05.

CLOUDINESS FOR ASOS STATIONS DIFFERS FROM THE NON–ASOS OBSERVATION TAKEN BY A HUMAN OBSERVER. ASOS STATION CLOUDINESS IS BASED ON TIME–AVERAGED CEILOMETER DATA FOR CLOUDS AT OR BELOW 12,000 FEET AND ON SATELLITE DATA FOR CLOUDS ABOVE 12,000 FEET.

THE NUMBER OF DAYS WITH CLEAR, PARTLY CLOUDY, AND CLOUDY CONDITIONS FOR ASOS STATIONS IS THE SUM OF THE CEILOMETER AND SATELLITE DATA FOR THE SUNRISE TO SUNSET PERIOD.

GENERAL CONTINUED:

CLEAR INDICATES 0–2 OKTAS, PARTLY CLOUDY INDICATES 3–6 OKTAS, AND CLOUDY INDICATES 7 OR 8 OKTAS. WHEN AT LEAST ONE OF THE ELEMENTS (CEILOMETER OR SATELLITE) IS MISSING, THE DAILY CLOUDINESS IS NOT COMPUTED.

WIND DIRECTION IS RECORDED IN TENS OF DEGREES (2 DIGITS) CLOCKWISE FROM TRUE NORTH. "00" INDICATES CALM. "36" INDICATES TRUE NORTH.

RESULTANT WIND IS THE VECTOR AVERAGE OF THE SPEED AND DIRECTION.

AVERAGE TEMPERATURE IS THE SUM OF THE MEAN DAILY MAXIMUM AND MINIMUM TEMPERATURE DIVIDED BY 2.

SNOWFALL DATA COMPRISE ALL FORMS OF FROZEN PRECIPITATION, INCLUDING HAIL.

A HEATING (COOLING) DEGREE DAY IS THE DIFFERENCE BETWEEN THE AVERAGE DAILY TEMPERATURE AND 65 F.

DRY BULB IS THE TEMPERATURE OF THE AMBIENT AIR.

DEW POINT IS THE TEMPERATURE TO WHICH THE AIR MUST BE COOLED TO ACHIEVE 100 PERCENT RELATIVE HUMIDITY.

WET BULB IS THE TEMPERATURE THE AIR WOULD HAVE IF THE MOISTURE CONTENT WAS INCREASED TO 100 PERCENT RELATIVE HUMIDITY.

ON JULY 1, 1996, THE NATIONAL WEATHER SERVICE BEGAN USING THE "METAR" OBSERVATION CODE THAT WAS ALREADY EMPLOYED BY MOST OTHER NATIONS OF THE WORLD. THE MOST NOTICEABLE DIFFERENCE IN THIS ANNUAL PUBLICATION WILL BE THE CHANGE IN UNITS FROM TENTHS TO EIGHTS (OKTAS) FOR REPORTING THE AMOUNT OF SKY COVER.

2001 Washington, D.C. Ronald Reagan National Airport (DCA)

HEATING DEGREE DAYS (base 65 F) 2001 WASHINGTON, D.C. DC (DCA)
YEAR JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN TOTAL
1972-73 0 0 8 278 543 654 843 777 423 286 109 0 3921
1973-74 0 0 4 103 399 708 677 716 490 228 85 4 3414
1974-75 0 0 26 250 446 674 740 677 608 345 24 0 3790
1975-76 0 0 20 102 328 752 956 524 415 236 80 0 3413
1976-77 0 0 11 306 652 907 1221 729 389 188 32 3 4438
1977-78 0 0 1 196 406 829 1001 933 633 219 86 0 4304
1978-79 0 0 9 192 378 671 918 1019 425 273 30 0 3915
1979-80 0 0 5 231 313 654 857 830 573 149 28 0 3640
1980-81 0 0 4 189 487 774 984 592 536 133 75 0 3774
1981-82 0 0 19 219 399 818 1135 743 592 328 19 3 4275
1982-83 0 2 9 193 402 597 827 730 497 365 77 0 3699
1983-84 0 0 32 177 433 890 1009 610 710 302 95 4 4262
1984-85 0 0 54 59 561 594 1053 757 533 166 30 6 3813
1985-86 0 0 14 147 320 879 913 824 542 267 61 3 3970
1986-87 0 13 18 180 548 775 931 777 527 304 68 0 4141
1987-88 0 0 4 325 448 719 1047 796 544 317 69 25 4294
1988-89 0 0 18 330 442 807 771 755 596 297 112 0 4128
1989-90 0 0 35 167 507 1144 656 550 481 285 64 4 3893
1990-91 0 0 38 153 381 630 810 608 502 237 22 0 3381
1991-92 0 0 27 175 486 696 824 686 614 295 127 5 3935
1992-93 0 0 43 282 477 781 779 855 700 307 32 3 4259
1993-94 0 0 33 217 487 825 1115 796 599 135 132 0 4339
1994-95 0 0 5 190 348 639 782 853 485 274 59 0 3635
1995-96 0 0 30 144 651 901 993 798 675 268 131 0 4591
1996-97 0 0 9 182 617 677 861 564 499 322 110 30 3871
1997-98 0 0 14 232 557 737 675 596 581 229 50 11 3682
1998-99 0 0 4 153 433 638 824 667 630 251 34 3 3637
1999-00 0 0 22 240 348 707 896 649 408 280 46 2 3598
2000-01 0 60 171 544 1022 908 670 654 246 54 4
2001- 0 0 44 207 302 598

2001 Washington, D.C. Ronald Reagan National Airport (DCA)

COOLING DEGREE DAYS (base 65 F) 2001 WASHINGTON, D.C. DC (DCA)
YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
1972 0 0 3 5 50 184 393 346 195 8 2 0 1186
1973 0 0 2 21 47 371 448 469 288 57 3 0 1706
1974 0 0 4 33 96 205 441 422 192 17 27 0 1437
1975 1 0 0 12 177 344 448 475 132 50 15 0 1654
1976 0 4 1 92 86 383 424 370 179 15 0 0 1554
1977 0 0 10 49 177 289 496 434 274 18 15 0 1762
1978 0 0 0 10 117 358 434 514 274 25 0 0 1732
1979 0 0 14 9 120 231 431 425 208 39 2 0 1479
1980 0 0 0 9 174 301 546 563 374 38 1 0 2006
1981 0 0 6 49 118 417 478 380 204 18 0 0 1670
1982 0 0 0 6 155 244 479 330 185 51 13 1 1464
1983 0 0 0 21 81 310 510 504 269 42 0 0 1737
1984 0 0 0 4 99 368 365 404 157 73 0 0 1470
1985 0 0 6 70 135 232 444 373 228 37 6 0 1531
1986 0 0 5 10 162 358 503 318 202 70 1 0 1629
1987 0 0 0 8 146 347 554 431 222 0 0 0 1708
1988 0 0 1 4 101 313 534 490 144 11 0 0 1598
1989 0 0 16 14 91 362 417 381 233 33 1 0 1548
1990 0 0 30 46 50 309 451 364 183 88 0 0 1521
1991 0 0 5 38 278 362 517 472 214 41 5 0 1932
1992 0 0 0 16 53 214 457 285 175 8 0 0 1208
1993 0 0 0 5 114 319 569 460 218 9 8 0 1702
1994 0 0 1 53 82 439 530 333 166 11 6 0 1621
1995 0 0 0 20 91 297 515 511 216 67 1 0 1718
1996 0 0 0 29 105 373 397 364 181 14 0 0 1463
1997 0 0 1 0 52 282 484 399 184 72 0 0 1474
1998 0 0 27 11 132 257 438 456 322 9 0 5 1657
1999 0 0 0 4 111 301 565 462 180 6 0 0 1629
2000 0 0 4 5 143 300 307 319 146 29 0 0 1253
2001 0 0 0 31 88 318 323 441 171 47 5 0 1424

2001 Washington, D.C. Ronald Reagan National Airport (DCA)

SNOWFALL (inches) 2001 WASHINGTON, D.C. DC (DCA)
YEAR JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN TOTAL
1972-73 0.0 0.0 0.0 T T 0.0 T 0.1 T T 0.0 0.0 0.1
1973-74 0.0 0.0 0.0 0.0 0.0 11.0 1.5 4.2 T T 0.0 0.0 16.7
1974-75 0.0 0.0 0.0 T T 0.1 6.6 5.8 0.3 T 0.0 0.0 12.8
1975-76 0.0 0.0 0.0 0.0 0.0 0.4 0.1 0.9 0.8 0.0 0.0 0.0 2.2
1976-77 0.0 0.0 0.0 0.0 0.8 0.6 9.7 0.0 0.0 T 0.0 0.0 11.1
1977-78 0.0 0.0 0.0 0.0 0.1 0.2 10.3 3.8 8.3 0.0 0.0 0.0 22.7
1978-79 0.0 0.0 0.0 0.0 3.1 T 4.0 30.6 T 0.0 0.0 0.0 37.7
1979-80 0.0 0.0 0.0 0.3 0.0 T 8.6 5.1 6.1 0.0 0.0 0.0 20.1
1980-81 0.0 0.0 0.0 0.0 T 0.3 4.2 T T 0.0 0.0 0.0 4.5
1981-82 0.0 0.0 0.0 0.0 T 1.7 15.3 5.3 0.2 T 0.0 0.0 22.5
1982-83 0.0 0.0 0.0 0.0 0.0 6.6 T 21.0 0.0 T 0.0 0.0 27.6
1983-84 0.0 0.0 0.0 0.0 0.3 T 6.5 T 1.8 T 0.0 0.0 8.6
1984-85 0.0 0.0 0.0 0.0 T 0.3 10.0 T T T 0.0 0.0 10.3
1985-86 0.0 0.0 0.0 0.0 0.0 0.7 1.8 12.9 T T 0.0 0.0 15.4
1986-87 0.0 0.0 0.0 0.0 0.0 T 20.8 10.3 T T 0.0 0.0 31.1
1987-88 0.0 0.0 0.0 0.0 11.5 T 13.1 T 0.4 T 0.0 0.0 25.0
1988-89 0.0 0.0 0.0 0.0 0.0 1.2 2.9 1.2 0.4 0.0 0.0 0.0 5.7
1989-90 0.0 0.0 0.0 0.0 3.5 9.0 0.2 T 2.4 0.2 0.0 0.0 15.3
1990-91 T 0.0 0.0 0.0 0.0 3.0 4.8 0.3 T 0.0 T 0.0 8.1
1991-92 0.0 0.0 0.0 0.0 T 0.0 4.0 2.6 T 0.0 0.0 0.0 6.6
1992-93 0.0 T 0.0 0.0 T 1.0 T 4.1 6.6 0.0 T 0.0 11.7
1993-94 0.0 0.0 0.0 0.0 T 2.6 3.5 3.1 4.0 0.0 0.0 0.0 13.2
1994-95 0.0 0.0 0.0 0.0 T 0.0 3.9 5.8 0.4 0.0 0.0 0.0 10.1
1995-96 0.0 0.0 0.0 0.0 0.5 1.3 23.8 15.2 5.2 T 0.0 0.0 46.0
1996-97 0.0 T 0.0 0.0 0.2 0.2 2.3 4.0 T 0.0 0.0 0.0 6.7
1997-98 0.0 0.0 0.0 0.0 T 0.1 T T T 0.0 T T 0.1
1998-99 0.0 0.0 0.0 0.0 0.0 0.5 2.2 0.2 8.7 0.0 0.0 0.0 11.6
1999-00 0.0 0.0 0.0 0.0 0.0 T 14.5 0.9 0.0 T 0.0 0.0 15.4
2000-01 0.0 T 0.0 0.0 0.0 2.0 2.4 2.8 0.2 T 0.0 0.0 7.4
2001- 0.0 0.0 0.0 0.0 0.0 0.0
POR=57 YRS T T 0.0 0.0 0.8 2.8 5.3 5.1 2.2 0.0 T 0.0 16.2



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