LEWISTOWN FAA AP, MONTANA

NCDC 1971-2000 Monthly Normals

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Monthly
Mean Max. Temperature (F) 31.9 36.3 42.9 53.2 62.6 71.5 79.5 79.9 68.7 57.3 42.0 34.2 55.0
Highest Mean Max. Temperature (F) 45.5 49.4 53.8 63.4 70.5 83.9 86.2 90.9 78.6 62.8 54.2 44.7 90.9
Year Highest Occurred 1981 1991 1986 1987 1985 1988 1985 1971 1990 1974 1999 1979 1971
Lowest Mean Max. Temperature (F) 14.6 19.5 31.1 37.1 54.4 62.8 67.7 71.4 56.3 51.2 20.2 17.2 14.6
Year Lowest Occurred 1979 1989 1996 1975 1996 1998 1993 1993 1985 1991 1985 1983 1979
Mean Temperature (F) 21.3 25.5 32.1 41.2 50.1 58.2 64.5 64.6 54.6 44.2 31.1 23.4 42.6
Highest Mean Temperature (F) 33.5 38.4 41.4 47.8 55.4 67.2 69.1 73.3 61.7 48.4 41.9 31.8 73.3
Year Highest Occurred 1983 1991 1986 1987 1985 1988 1985 1971 1998 1974 1999 1999 1971
Lowest Mean Temperature (F) 3.5 9.3 22.7 28.2 45.4 52.9 56.4 58.4 46.9 38.4 10.5 6.1 3.5
Year Lowest Occurred 1979 1989 1996 1975 1996 1998 1993 1977 1985 1984 1985 1983 1979
Mean Min. Temperature (F) 10.6 14.7 21.3 29.2 37.6 44.9 49.5 49.2 40.4 31.1 20.1 12.6 30.1
Highest Mean Min. Temperature (F) 22.4 27.4 28.9 34.6 40.8 50.4 54.0 55.6 46.9 34.7 29.6 22.4 55.6
Year Highest Occurred 1983 1991 1986 1980 1987 1988 1975 1971 1998 1983 1999 1999 1971
Lowest Mean Min. Temperature (F) -7.6 -0.9 14.2 19.2 34.9 41.1 45.1 43.6 36.7 25.6 0.9 -4.9 -7.6
Year Lowest Occurred 1979 1989 1996 1975 1979 1981 1993 1987 1984 1984 1985 1983 1979
Mean Precipitation (in.) 0.89 0.57 1.16 1.38 2.92 2.93 2.10 1.89 1.38 1.06 0.74 0.83 17.85
Highest Precipitation (in.) 2.75 1.97 2.62 2.92 9.16 6.47 5.46 5.54 3.77 2.43 1.57 2.36 9.16
Year Highest Occurred 1978 1979 1975 1994 1981 1973 1993 1985 1978 1981 1991 1977 1981
Lowest Precipitation (in.) 0.10 0.09 0.35 0.36 0.82 0.99 0.11 0.20 0.00 0.16 0.07 0.17 0.00
Year Lowest Occurred 1983 1987 1978 1985 1984 1974 1984 2000 1990 1987 1988 1986 1990
Heating Degree Days (F) 1355. 1105. 1020. 715. 462. 226. 106. 135. 335. 645. 1018. 1291. 8413.
Cooling Degree Days (F) 0. 0. 0. 0. 0. 22. 90. 121. 22. 0. 0. 0. 255.
Western Regional Climate Center, wrcc@dri.edu