SWAN FALLS POWER HOUSE, IDAHO

NCDC 1971-2000 Monthly Normals

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Monthly
Mean Max. Temperature (F) 39.6 48.0 58.2 66.6 75.7 85.6 94.5 93.3 83.0 69.2 50.8 40.2 67.1
Highest Mean Max. Temperature (F) 48.0 56.0 66.2 77.1 85.3 93.4 100.2 98.6 90.5 79.6 59.3 46.1 100.2
Year Highest Occurred 1998 1992 1992 1987 1992 1986 1985 1971 1990 1988 1999 1977 1985
Lowest Mean Max. Temperature (F) 27.5 36.8 52.1 56.7 68.7 79.4 84.4 85.7 74.6 64.5 40.3 24.0 24.0
Year Lowest Occurred 1979 1989 1976 1975 1998 1998 1993 1976 1985 1984 1985 1985 1985
Mean Temperature (F) 31.6 38.0 46.5 53.7 62.1 70.9 78.6 77.2 67.2 55.3 41.0 32.1 54.5
Highest Mean Temperature (F) 39.5 43.3 51.7 60.2 67.7 77.0 84.3 81.9 73.1 63.6 48.2 38.6 84.3
Year Highest Occurred 1998 1986 1986 1987 1992 1986 1985 1971 1990 1988 1999 1973 1985
Lowest Mean Temperature (F) 20.0 27.2 40.6 46.9 58.5 66.4 69.7 71.8 61.2 50.7 31.6 16.9 16.9
Year Lowest Occurred 1979 1989 1985 1975 1977 1993 1993 1976 1985 1984 1985 1985 1985
Mean Min. Temperature (F) 23.5 27.9 34.7 40.8 48.5 56.1 62.7 61.0 51.4 41.3 31.1 23.9 41.9
Highest Mean Min. Temperature (F) 31.3 34.4 39.6 45.2 52.7 61.5 68.3 65.1 57.9 47.6 37.1 31.3 68.3
Year Highest Occurred 1978 1986 1986 1990 1987 1977 1985 1971 1998 1988 1999 1973 1985
Lowest Mean Min. Temperature (F) 12.4 17.6 28.8 35.5 44.8 52.5 54.9 56.0 46.7 36.8 21.1 9.7 9.7
Year Lowest Occurred 1979 1989 1985 1982 1984 1993 1993 1995 1972 1984 1993 1985 1985
Mean Precipitation (in.) 0.83 0.59 0.96 1.01 1.06 0.68 0.29 0.22 0.53 0.53 0.89 0.81 8.40
Highest Precipitation (in.) 1.85 2.19 2.34 3.32 3.48 2.25 1.36 0.97 2.86 1.60 2.23 2.39 3.48
Year Highest Occurred 1972 1986 1983 1981 1998 1984 1983 1979 1986 1975 1988 1996 1998
Lowest Precipitation (in.) 0.11 0.10 0.02 0.18 0.04 0.04 0.00 0.00 0.00 0.00 0.12 0.00 0.00
Year Lowest Occurred 1985 1973 1992 1974 1992 2000 2000 1998 1999 1988 1976 1989 2000
Heating Degree Days (F) 1037. 758. 575. 351. 144. 32. 2. 3. 68. 309. 721. 1022. 5022.
Cooling Degree Days (F) 0. 0. 0. 11. 55. 206. 423. 379. 133. 7. 0. 0. 1214.

Western Regional Climate Center, wrcc@dri.edu