YELLOWTAIL DAM, MONTANA

NCDC 1961-1990 Monthly Normals

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Mean Max. Temperature (F) 38.6 44.1 51.5 62.3 71.6 81.3 90.7 90.0 77.7 66.5 49.8 40.9 63.8
Highest Mean Max. Temperature (F) 51.6 54.4 62.5 73.9 78.4 95.8 97.0 96.9 86.9 75.1 57.0 53.8 68.1
Year Highest Occurred 1986 1961 1986 1987 1985 1988 1988 1970 1990 1963 1963 1962 1988
Lowest Mean Max. Temperature (F) 23.4 28.4 39.2 50.3 66.3 73.5 85.8 83.5 61.4 51.3 29.1 20.5 59.7
Year Lowest Occurred 1979 1989 1965 1975 1975 1967 1972 1977 1965 1969 1985 1983 1978
Mean Temperature (F) 27.6 33.0 39.3 49.3 58.2 66.9 74.5 73.4 62.5 52.9 39.0 30.3 50.6
Highest Mean Temperature (F) 41.3 42.2 50.3 56.5 62.8 76.8 77.9 80.2 69.8 58.4 45.7 39.9 53.5
Year Highest Occurred 1986 1977 1986 1987 1985 1988 1966 1983 1990 1963 1981 1979 1988
Lowest Mean Temperature (F) 12.1 17.5 25.9 39.9 54.1 60.6 70.2 68.1 50.0 41.7 21.0 11.3 47.5
Year Lowest Occurred 1969 1989 1965 1975 1975 1967 1972 1987 1965 1969 1985 1983 1978
Mean Min. Temperature (F) 16.5 21.8 27.1 36.3 44.7 52.5 58.2 56.7 47.4 39.3 28.1 19.6 37.4
Highest Mean Min. Temperature (F) 30.9 32.7 38.0 42.3 48.0 57.8 61.6 64.5 52.9 43.7 34.7 29.0 40.8
Year Highest Occurred 1986 1977 1986 1985 1987 1988 1985 1983 1963 1979 1981 1976 1981
Lowest Mean Min. Temperature (F) -0.4 6.6 12.6 29.5 40.3 47.6 54.4 51.9 38.5 32.0 12.8 2.1 34.6
Year Lowest Occurred 1969 1989 1965 1975 1967 1967 1971 1964 1965 1969 1985 1983 1966
Mean Precipitation (in.) 0.97 0.73 1.33 2.37 3.24 2.51 1.20 1.15 1.93 1.56 0.99 0.87 18.85
Highest Precipitation (in.) 2.36 1.86 3.05 7.46 9.28 7.52 5.22 3.55 4.26 6.14 2.41 2.51 27.98
Year Highest Occurred 1963 1986 1973 1963 1978 1967 1981 1965 1961 1971 1968 1989 1978
Lowest Precipitation (in.) 0.11 0.00 0.17 0.33 1.04 0.50 0.01 0.04 0.09 0.11 0.26 0.08 12.33
Year Lowest Occurred 1961 1969 1978 1981 1976 1961 1964 1970 1964 1978 1963 1986 1979
Heating Degree Days (F) 1159. 896. 797. 478. 223. 78. 0. 20. 172. 383. 780. 1076. 6062.
Cooling Degree Days (F) 0. 0. 0. 7. 12. 135. 298. 280. 97. 8. 0. 0. 837.

Western Regional Climate Center, wrcc@dri.edu