SEATTLE TCOMA WSCMO AP, WASHINGTON

NCDC 1971-2000 Monthly Normals

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Monthly
Mean Max. Temperature (F) 45.8 49.5 53.2 58.2 64.4 69.6 75.3 75.6 70.2 59.7 50.5 45.5 59.8
Highest Mean Max. Temperature (F) 52.0 55.9 59.1 63.2 71.2 75.8 80.9 80.0 76.0 65.4 55.3 49.8 80.9
Year Highest Occurred 1995 1977 1992 1977 1992 1992 1985 1986 1974 1987 1997 1976 1985
Lowest Mean Max. Temperature (F) 39.9 43.2 47.4 53.6 59.6 63.7 68.7 70.9 64.1 56.4 40.6 40.1 39.9
Year Lowest Occurred 1980 1989 1971 1975 1999 1971 1993 1980 1972 1984 1985 1990 1980
Mean Temperature (F) 40.9 43.3 46.2 50.2 55.8 60.7 65.3 65.6 61.1 52.7 45.2 40.7 52.3
Highest Mean Temperature (F) 46.4 48.7 50.3 53.6 60.1 65.0 68.6 68.5 64.4 55.8 49.1 44.7 68.6
Year Highest Occurred 1995 1977 1992 1977 1995 1992 1985 1977 1994 1987 1995 1976 1985
Lowest Mean Temperature (F) 34.8 35.9 41.3 45.8 51.8 56.4 61.2 61.9 55.9 49.7 35.8 35.3 34.8
Year Lowest Occurred 1980 1989 1976 1975 1999 1971 1993 1980 1972 1984 1985 1990 1980
Mean Min. Temperature (F) 35.9 37.2 39.1 42.1 47.2 51.7 55.3 55.7 51.9 45.7 39.9 35.9 44.8
Highest Mean Min. Temperature (F) 40.7 41.5 42.9 44.5 50.5 54.1 57.8 57.7 54.9 49.2 43.7 40.2 57.8
Year Highest Occurred 1995 1977 1983 1994 1993 1992 1998 1994 1994 1988 1995 1973 1998
Lowest Mean Min. Temperature (F) 29.7 28.5 34.3 38.0 44.0 49.0 53.1 52.4 47.6 42.9 30.9 30.4 28.5
Year Lowest Occurred 1980 1989 1976 1975 1999 1971 1999 1973 1972 1984 1985 1990 1989
Mean Precipitation (in.) 5.13 4.18 3.75 2.59 1.78 1.49 0.79 1.02 1.63 3.19 5.90 5.62 37.07
Highest Precipitation (in.) 9.41 8.35 8.15 6.53 3.70 3.05 2.39 4.59 5.95 7.75 11.62 11.85 11.85
Year Highest Occurred 1990 1996 1997 1991 1977 1990 1983 1975 1978 1975 1998 1979 1979
Lowest Precipitation (in.) 0.58 0.35 1.55 0.55 0.12 0.16 0.08 0.01 0.00 0.31 0.74 1.37 0.00
Year Lowest Occurred 1985 1993 1979 1977 1992 1987 1973 1974 1991 1987 1976 1978 1991
Heating Degree Days (F) 747. 613. 582. 447. 291. 150. 55. 45. 138. 383. 592. 754. 4797.
Cooling Degree Days (F) 0. 0. 0. 0. 5. 19. 65. 65. 19. 0. 0. 0. 173.

Western Regional Climate Center, wrcc@dri.edu