Idaho September Temperature by Year

This page is a list of the average statewide temperature in the month of September in Idaho for each year from 1895–2023. It is a statewide average over the entire territory of the state, based on data from the NOAA.
State:
Month:
What Was the Hottest September in Idaho History?
1990 was the warmest September in Idaho history. Statewide, the average daily high temperature was 77.8 °F, and the average low was 45.5 °F.
What Was the Coldest September in Idaho History?
1912 was the coolest September in Idaho history. Statewide, the average daily high temperature was 62.0 °F, and the average low was 35.3 °F.
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Year Rank High (°F) Low (°F)
2023 37 70.2 43.1
2022 2 76.4 45.3
2021 26 72.8 41.4
2020 12 74.8 42.6
2019 66 67.6 42.4
2018 43 71.7 40.6
2017 53 69.0 42.4
2016 77 67.8 41.5
2015 24 71.9 42.5
2014 19 71.9 43.4
2013 26 69.2 45.0
2012 13 74.9 42.0
2011 7 75.7 43.4
2010 41 71.6 41.2
2009 5 76.4 43.9
2008 56 71.3 39.7
2007 70 69.4 40.4
2006 64 70.0 40.1
2005 88 69.2 38.9
2004 96 67.0 40.4
2003 34 71.9 41.4
2002 48 70.6 41.2
2001 9 75.4 43.3
2000 89 68.1 39.9
1999 86 70.5 38.0
1998 3 74.3 46.4
1997 22 71.0 43.8
1996 107 66.6 38.4
1995 33 71.9 41.6
1994 10 75.1 42.6
1993 77 70.2 38.9
1992 86 69.0 39.4
1991 28 72.2 41.9
1990 1 77.8 45.5
1989 53 71.2 40.2
1988 83 69.7 39.3
1987 15 75.2 40.3
1986 123 60.6 39.1
1985 126 60.7 37.7
1984 107 66.4 38.6
1983 89 68.1 39.8
1982 93 66.3 41.5
1981 37 72.2 41.0
1980 59 68.4 42.1
1979 13 75.4 41.3
1978 99 65.8 41.0
1977 96 66.8 40.7
1976 43 70.7 41.8
1975 58 72.1 38.5
1974 50 73.2 38.3
1973 89 67.5 40.5
1972 116 63.9 38.0
1971 121 64.0 36.0
1970 123 63.5 36.3
1969 39 71.2 41.8
1968 98 66.7 40.5
1967 7 75.4 43.8
1966 10 73.5 44.3
1965 128 61.0 36.2
1964 114 66.9 37.3
1963 6 73.4 46.0
1962 45 72.3 39.8
1961 121 62.2 37.9
1960 24 72.9 41.5
1959 111 63.4 41.4
1958 77 69.2 40.0
1957 39 73.3 39.6
1956 55 72.4 38.9
1955 84 69.4 39.5
1954 77 70.0 39.3
1953 17 74.4 41.0
1952 17 74.8 40.5
1951 70 70.7 39.1
1950 70 68.5 41.2
1949 28 72.7 41.3
1948 66 70.3 39.7
1947 59 69.8 40.6
1946 99 67.7 39.1
1945 113 65.9 38.4
1944 50 71.2 40.4
1943 15 75.2 40.5
1942 48 71.9 39.9
1941 120 61.8 38.5
1940 34 67.8 45.6
1939 46 71.3 40.8
1938 4 76.1 44.3
1937 19 73.5 41.8
1936 95 69.8 37.8
1935 21 74.6 40.4
1934 104 67.6 38.0
1933 101 68.2 38.3
1932 66 72.3 37.6
1931 77 68.3 40.9
1930 70 69.0 40.8
1929 116 65.3 36.6
1928 56 72.6 38.5
1927 107 64.6 40.4
1926 126 63.6 34.7
1925 77 67.6 41.6
1924 75 70.4 39.1
1923 32 72.2 41.5
1922 22 74.0 40.8
1921 125 63.4 35.9
1920 85 67.3 41.3
1919 59 69.4 41.0
1918 28 71.0 42.9
1917 28 72.3 41.6
1916 89 69.1 38.9
1915 107 65.6 39.3
1914 112 66.3 38.4
1913 75 69.8 39.6
1912 128 62.0 35.3
1911 106 66.7 38.5
1910 59 69.2 41.2
1909 59 67.6 42.8
1908 70 69.3 40.5
1907 93 68.5 39.3
1906 46 71.5 40.4
1905 50 70.8 40.7
1904 41 72.1 40.7
1903 115 65.2 37.4
1902 101 69.2 37.2
1901 119 63.5 37.7
1900 104 66.1 39.6
1899 34 72.9 40.6
1898 66 70.9 39.0
1897 64 68.9 41.4
1896 103 66.6 39.5
1895 116 63.6 38.3