SAINT HELENA, CALIFORNIA

NCDC 1961-1990 Monthly Normals

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Mean Max. Temperature (F) 56.9 62.0 64.7 70.8 78.2 84.6 89.3 88.5 85.2 77.4 64.6 57.3 73.3
Highest Mean Max. Temperature (F) 63.1 68.0 70.9 79.5 85.1 91.7 94.0 94.4 92.4 83.6 71.2 65.5 75.0
Year Highest Occurred 1976 1988 1984 1987 1984 1981 1961 1969 1984 1965 1986 1976 1984
Lowest Mean Max. Temperature (F) 51.6 54.0 60.5 56.6 71.3 77.7 85.3 84.3 77.7 70.1 58.3 51.5 71.1
Year Lowest Occurred 1969 1969 1975 1967 1977 1965 1987 1976 1986 1972 1973 1965 1975
Mean Temperature (F) 46.2 50.3 52.4 56.4 62.5 68.0 71.1 70.7 67.7 61.8 52.5 46.6 58.9
Highest Mean Temperature (F) 52.0 55.4 57.0 62.7 67.7 73.9 75.0 74.5 72.5 65.0 56.1 50.8 61.3
Year Highest Occurred 1984 1963 1984 1987 1984 1981 1988 1981 1984 1987 1981 1977 1981
Lowest Mean Temperature (F) 42.9 45.5 49.3 46.6 57.5 63.7 68.1 68.1 63.3 57.8 49.0 41.8 57.1
Year Lowest Occurred 1963 1969 1973 1967 1977 1965 1966 1976 1986 1971 1972 1972 1971
Mean Min. Temperature (F) 35.5 38.6 40.0 42.1 46.7 51.3 52.8 52.8 50.2 46.1 40.4 36.0 44.4
Highest Mean Min. Temperature (F) 43.6 44.8 45.3 48.2 51.1 56.0 56.7 59.1 54.3 49.9 46.4 43.5 47.8
Year Highest Occurred 1984 1986 1978 1985 1987 1981 1985 1981 1981 1987 1981 1983 1981
Lowest Mean Min. Temperature (F) 30.0 33.4 35.4 36.6 43.1 48.5 49.2 49.4 46.1 40.2 36.1 28.7 42.1
Year Lowest Occurred 1963 1964 1976 1967 1964 1971 1962 1970 1965 1971 1978 1990 1971
Mean Precipitation (in.) 7.95 5.93 4.71 1.88 0.45 0.15 0.05 0.13 0.43 2.06 5.51 5.94 35.19
Highest Precipitation (in.) 19.75 25.60 14.53 6.82 4.91 1.89 1.08 0.82 1.95 11.77 15.25 14.22 75.40
Year Highest Occurred 1970 1986 1983 1982 1990 1967 1974 1965 1982 1962 1973 1964 1983
Lowest Precipitation (in.) 0.48 0.15 0.15 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.12 0.00 10.41
Year Lowest Occurred 1976 1964 1988 1973 1987 1990 1990 1990 1988 1978 1986 1989 1976
Heating Degree Days (F) 583. 412. 391. 284. 123. 30. 5. 0. 31. 123. 375. 570. 2927.
Cooling Degree Days (F) 0. 0. 0. 26. 45. 120. 194. 179. 112. 24. 0. 0. 700.

Western Regional Climate Center, wrcc@dri.edu