YELLOWTAIL DAM, MONTANA

NCDC 1971-2000 Monthly Normals

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Monthly
Mean Max. Temperature (F) 40.2 46.1 54.0 63.4 72.7 82.7 91.0 91.0 79.2 66.1 49.0 41.7 64.8
Highest Mean Max. Temperature (F) 53.0 56.3 63.8 74.9 79.3 95.8 97.0 99.1 86.9 71.8 63.6 52.7 99.1
Year Highest Occurred 1986 1992 1986 1987 1985 1988 1988 1971 1990 1974 1999 1979 1971
Lowest Mean Max. Temperature (F) 24.8 28.4 43.1 52.9 64.4 73.2 78.5 84.0 69.6 61.1 29.5 21.4 21.4
Year Lowest Occurred 1979 1989 1996 1975 1996 1998 1993 1993 1986 1971 1985 1983 1983
Mean Temperature (F) 29.0 34.0 41.0 49.8 58.6 67.6 74.1 73.6 63.2 52.3 38.4 31.1 51.1
Highest Mean Temperature (F) 42.0 42.8 50.9 57.0 63.2 76.8 78.2 80.5 70.0 56.5 49.2 40.2 80.5
Year Highest Occurred 1986 1999 1986 1987 1985 1988 1985 1983 1998 1973 1999 1999 1983
Lowest Mean Temperature (F) 13.0 17.5 32.1 40.2 53.3 61.5 65.9 68.4 58.3 49.0 21.2 11.8 11.8
Year Lowest Occurred 1979 1989 1996 1975 1995 1998 1993 1987 1986 1984 1985 1983 1983
Mean Min. Temperature (F) 17.7 21.9 28.0 36.2 44.5 52.4 57.2 56.1 47.2 38.5 27.7 20.5 37.3
Highest Mean Min. Temperature (F) 30.9 32.0 38.0 42.3 48.4 57.8 61.6 64.5 53.8 42.0 34.8 31.3 64.5
Year Highest Occurred 1986 1999 1986 1985 1994 1988 1985 1983 1998 1986 1999 1999 1983
Lowest Mean Min. Temperature (F) 1.3 6.6 20.9 27.5 40.0 48.6 52.7 51.2 43.2 34.1 12.8 2.1 1.3
Year Lowest Occurred 1979 1989 1989 1975 1975 1982 1971 1974 1971 1972 1985 1983 1979
Mean Precipitation (in.) 0.86 0.72 1.39 2.10 3.09 2.21 1.45 0.98 1.77 1.89 0.95 0.87 18.28
Highest Precipitation (in.) 1.67 1.86 3.05 5.67 9.28 7.81 5.22 2.89 5.13 6.14 2.26 2.51 9.28
Year Highest Occurred 1978 1986 1973 1978 1978 1992 1981 1987 1991 1971 1991 1989 1978
Lowest Precipitation (in.) 0.12 0.02 0.17 0.33 0.12 0.58 0.07 0.07 0.18 0.11 0.32 0.08 0.02
Year Lowest Occurred 1990 1992 1978 1981 1998 1971 1988 1994 1990 1978 1987 1986 1992
Heating Degree Days (F) 1118. 869. 744. 460. 224. 65. 11. 23. 131. 395. 801. 1051. 5892.
Cooling Degree Days (F) 0. 0. 0. 5. 25. 142. 293. 287. 77. 1. 0. 0. 830.
Western Regional Climate Center, wrcc@dri.edu