NATIONAL ARBORETUM DC, MARYLAND

NCDC 1971-2000 Monthly Normals

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Mean Max. Temperature (F) 43.0 46.4 55.3 66.0 75.8 84.4 88.9 87.4 80.4 69.0 58.0 47.7 66.9
Highest Mean Max. Temperature (F) 51.8 56.7 62.3 72.3 83.2 88.7 94.6 92.2 87.9 74.4 64.0 55.8 94.6
Year Highest Occurred 1990 1976 2000 1994 1991 1994 1999 1999 1998 1990 1999 1984 1999
Lowest Mean Max. Temperature (F) 31.9 33.0 48.6 60.4 71.5 79.1 85.2 82.8 75.0 61.3 50.0 34.8 31.9
Year Lowest Occurred 1977 1979 1984 1975 1996 1972 1996 1992 1975 1976 1996 1989 1977
Mean Temperature (F) 33.5 36.2 44.4 54.1 64.1 73.1 77.9 76.1 68.7 56.6 46.9 38.0 55.8
Highest Mean Temperature (F) 42.2 43.8 50.1 59.5 71.5 77.2 83.1 79.6 75.1 63.0 52.0 44.0 83.1
Year Highest Occurred 1998 1976 2000 1994 1991 1994 1999 1999 1998 1971 1999 1971 1999
Lowest Mean Temperature (F) 23.5 24.1 38.4 49.7 60.2 68.9 74.8 72.4 64.3 49.9 41.2 26.3 23.5
Year Lowest Occurred 1977 1979 1984 1975 1997 1972 2000 1992 1988 1988 1996 1989 1977
Mean Min. Temperature (F) 24.0 26.0 33.4 42.2 52.4 61.8 66.9 64.8 56.9 44.1 35.7 28.2 44.7
Highest Mean Min. Temperature (F) 33.0 32.0 38.4 46.7 59.7 65.8 71.5 69.4 62.2 53.3 41.4 33.9 71.5
Year Highest Occurred 1998 1997 1977 1994 1991 1973 1999 1978 1998 1971 1985 1971 1999
Lowest Mean Min. Temperature (F) 15.1 15.2 28.3 36.6 48.5 58.3 63.6 60.5 50.2 34.5 30.5 17.7 15.1
Year Lowest Occurred 1977 1979 1984 1971 1997 1979 2000 1989 1988 1988 1984 1989 1977
Mean Precipitation (in.) 3.57 2.84 3.92 3.26 4.29 3.63 4.21 3.90 4.08 3.43 3.32 3.25 43.70
Highest Precipitation (in.) 7.58 6.49 8.45 7.45 8.49 12.77 11.03 7.63 13.72 8.16 6.88 6.61 13.72
Year Highest Occurred 1978 1972 1994 1983 1989 1972 1975 1971 1975 1976 1972 1983 1975
Lowest Precipitation (in.) 0.49 0.12 1.36 0.05 0.90 0.51 0.59 0.32 0.45 0.00 0.51 0.73 0.00
Year Lowest Occurred 1981 1987 1986 1985 1986 1988 1999 1989 1977 2000 1981 1980 2000
Heating Degree Days (F) 977. 807. 641. 332. 108. 6. 0. 1. 35. 283. 544. 837. 4571.
Cooling Degree Days (F) 0. 0. 0. 4. 80. 249. 399. 345. 144. 22. 0. 0. 1243.

Southeast Regional Climate Center, sercc@climate.ncsu.edu