SWAN FALLS POWER HOUSE, IDAHO

NCDC 1961-1990 Monthly Normals

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Mean Max. Temperature (F) 40.3 49.1 58.7 68.1 77.6 87.3 96.3 94.6 83.4 70.1 52.7 41.0 68.3
Highest Mean Max. Temperature (F) 47.7 56.3 64.9 78.8 84.2 95.6 101.1 100.2 91.3 80.4 57.5 46.7 71.2
Year Highest Occurred 1967 1963 1986 1987 1966 1961 1985 1967 1990 1988 1965 1977 1987
Lowest Mean Max. Temperature (F) 28.6 37.9 52.4 58.2 71.8 80.8 90.6 86.0 75.4 63.3 41.3 24.6 65.1
Year Lowest Occurred 1979 1989 1964 1975 1977 1984 1982 1968 1985 1969 1985 1985 1985
Mean Temperature (F) 32.4 39.2 46.7 54.3 63.0 71.8 79.7 77.8 67.3 55.9 43.0 33.1 55.4
Highest Mean Temperature (F) 39.9 46.0 52.6 61.2 67.6 78.7 84.7 82.6 73.4 64.2 47.4 39.2 57.0
Year Highest Occurred 1967 1963 1986 1987 1987 1961 1985 1971 1990 1988 1965 1973 1967
Lowest Mean Temperature (F) 21.1 28.4 41.5 47.8 59.1 65.5 75.5 72.4 61.6 51.0 32.7 17.5 51.8
Year Lowest Occurred 1979 1989 1985 1975 1977 1984 1982 1968 1985 1969 1985 1985 1985
Mean Min. Temperature (F) 24.4 29.4 34.6 40.5 48.3 56.3 63.1 60.9 51.1 41.6 33.2 25.2 42.4
Highest Mean Min. Temperature (F) 32.5 35.7 40.3 45.4 52.7 61.7 68.3 66.2 57.5 48.0 37.3 32.0 44.3
Year Highest Occurred 1978 1986 1986 1990 1987 1961 1985 1961 1963 1988 1965 1973 1967
Lowest Mean Min. Temperature (F) 13.6 18.9 29.5 35.7 44.8 50.1 59.5 53.2 46.0 37.2 24.1 10.4 38.5
Year Lowest Occurred 1979 1989 1985 1982 1984 1984 1987 1988 1970 1984 1985 1985 1985
Mean Precipitation (in.) 0.82 0.53 0.81 0.99 0.96 0.81 0.26 0.35 0.57 0.51 0.93 0.72 8.26
Highest Precipitation (in.) 2.53 2.19 2.34 3.32 3.44 2.42 1.36 2.49 2.86 1.60 2.23 2.46 12.47
Year Highest Occurred 1970 1986 1983 1981 1980 1963 1983 1968 1986 1975 1988 1964 1983
Lowest Precipitation (in.) 0.07 0.04 0.00 0.06 0.18 0.10 0.00 0.00 0.00 0.00 0.12 0.00 4.16
Year Lowest Occurred 1961 1964 1965 1961 1974 1989 1989 1973 1990 1988 1976 1989 1966
Heating Degree Days (F) 1011. 722. 567. 336. 112. 24. 0. 0. 76. 291. 660. 989. 4788.
Cooling Degree Days (F) 0. 0. 0. 15. 50. 228. 456. 397. 145. 9. 0. 0. 1300.

Western Regional Climate Center, wrcc@dri.edu