DIABLO DAM, WASHINGTON

NCDC 1961-1990 Monthly Normals

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Mean Max. Temperature (F) 38.2 43.5 49.3 56.5 64.6 71.0 76.7 77.7 70.3 58.1 44.9 38.4 57.4
Highest Mean Max. Temperature (F) 44.2 49.2 55.5 63.4 71.2 77.7 86.0 86.4 78.4 66.3 49.4 43.2 60.2
Year Highest Occurred 1981 1970 1981 1980 1969 1970 1985 1967 1974 1987 1976 1976 1987
Lowest Mean Max. Temperature (F) 27.4 36.4 43.6 51.1 58.1 63.3 70.5 70.2 62.5 52.3 33.4 31.7 55.2
Year Lowest Occurred 1969 1989 1971 1970 1984 1975 1983 1976 1978 1990 1985 1990 1975
Mean Temperature (F) 33.2 36.9 41.0 46.7 53.6 59.7 64.2 65.3 59.0 49.4 39.7 34.0 48.6
Highest Mean Temperature (F) 39.3 41.4 44.9 51.3 57.6 64.9 69.4 70.2 63.7 53.5 43.8 38.4 50.8
Year Highest Occurred 1981 1970 1981 1980 1983 1969 1985 1967 1967 1987 1987 1976 1987
Lowest Mean Temperature (F) 22.8 28.9 36.9 42.2 49.2 55.0 60.9 60.5 54.4 45.9 28.1 27.2 46.5
Year Lowest Occurred 1969 1989 1971 1975 1984 1971 1983 1975 1972 1990 1985 1983 1985
Mean Min. Temperature (F) 28.1 30.3 32.7 36.8 42.5 48.3 51.8 52.8 47.6 40.7 34.4 29.5 39.6
Highest Mean Min. Temperature (F) 34.4 34.2 35.9 40.0 45.2 52.6 55.3 55.6 51.1 44.4 38.7 34.3 41.3
Year Highest Occurred 1981 1961 1984 1987 1980 1969 1990 1977 1966 1988 1987 1966 1987
Lowest Mean Min. Temperature (F) 18.1 21.4 29.2 33.0 39.9 44.9 48.8 49.6 43.6 38.1 22.7 22.2 37.0
Year Lowest Occurred 1969 1989 1976 1975 1964 1976 1976 1975 1972 1972 1985 1983 1985
Mean Precipitation (in.) 11.93 8.30 6.96 4.75 3.24 2.23 1.71 1.82 3.81 7.63 13.16 12.51 78.05
Highest Precipitation (in.) 23.95 17.23 13.23 10.38 7.96 6.70 6.76 4.30 9.16 19.61 38.46 25.83 115.34
Year Highest Occurred 1974 1961 1988 1981 1984 1981 1983 1990 1972 1967 1990 1975 1990
Lowest Precipitation (in.) 0.98 1.39 1.31 1.71 0.88 0.20 0.05 0.03 0.16 0.39 2.76 1.74 56.56
Year Lowest Occurred 1985 1989 1965 1967 1967 1965 1984 1986 1990 1987 1979 1985 1987
Heating Degree Days (F) 986. 787. 744. 549. 353. 183. 84. 87. 203. 484. 759. 961. 6180.
Cooling Degree Days (F) 0. 0. 0. 0. 0. 24. 59. 96. 23. 0. 0. 0. 202.

Western Regional Climate Center, wrcc@dri.edu