Average September Temperature in Boise by Year

This page contains a list of the average monthly high and low temperatures in Boise, Idaho for the month of September each year between 1911 and 2023. It is based on NOAA data.
Change:
Month:
What Was the Hottest September Ever in Boise?
2011 was the warmest September in the history of Boise, Idaho. The average daily high temperature was 86.4 °F, and the average low was 56.3 °F.
What Was the Coldest September Ever in Boise?
1985 was the coolest September in the history of Boise, Idaho. The average daily high temperature was 68.8 °F, and the average low was 43.6 °F.
* click column headers to sort
Year Rank High (°F) Low (°F)
2023 11 81.0 55.4
2022 2 85.8 56.6
2021 22 81.5 51.5
2020 7 83.3 54.1
2019 41 77.3 52.6
2018 33 79.9 51.1
2017 24 78.5 53.9
2016 51 76.7 51.1
2015 21 80.1 53.1
2014 13 80.5 54.8
2013 20 77.9 55.3
2012 8 83.5 53.7
2011 1 86.4 56.3
2010 14 82.0 53.2
2009 4 84.5 56.6
2008 25 80.2 51.9
2007 42 78.5 51.0
2006 34 79.2 51.6
2005 59 77.5 49.1
2004 54 76.3 51.0
2003 17 80.6 52.8
2002 39 79.0 51.3
2001 10 82.8 53.9
2000 68 76.4 49.5
1999 47 78.9 49.1
1998 6 81.8 57.7
1997 12 81.0 54.4
1996 79 75.1 48.4
1995 29 80.9 50.5
1994 16 83.2 50.4
1993 66 79.5 46.6
1992 58 78.7 48.1
1991 28 81.1 50.4
1990 5 86.2 53.5
1989 60 78.7 47.9
1988 81 77.2 46.1
1987 30 82.2 49.0
1986 106 69.1 45.6
1985 112 68.8 43.6
1984 91 74.6 45.5
1983 88 76.2 45.4
1982 90 73.9 46.8
1981 55 79.0 48.3
1980 72 76.4 48.7
1979 15 83.5 51.1
1978 83 74.8 47.9
1977 76 75.5 48.4
1976 46 77.5 50.6
1975 32 82.4 48.6
1974 35 81.8 48.8
1973 65 76.9 49.3
1972 99 71.5 46.0
1971 98 72.5 45.8
1970 104 71.8 43.8
1969 44 78.1 50.2
1968 67 76.7 49.2
1967 9 82.8 54.4
1966 23 81.2 51.2
1965 108 70.1 44.1
1964 94 74.1 45.0
1963 3 84.5 57.3
1962 38 80.8 49.6
1961 107 70.8 43.5
1960 26 81.9 50.0
1959 93 71.3 48.1
1958 75 76.2 47.8
1957 37 80.6 50.0
1956 45 79.5 48.8
1955 73 76.9 47.9
1954 82 76.7 46.4
1953 27 81.6 50.3
1952 36 80.9 49.8
1951 53 78.2 49.1
1950 63 76.5 49.8
1949 31 80.7 50.5
1948 78 76.5 47.2
1947 70 77.5 48.2
1946 85 76.0 46.0
1945 92 74.7 45.1
1944 52 77.7 49.8
1943 19 82.5 50.8
1942 62 78.7 47.7
1941 103 71.2 44.6
1940 64 74.4 51.9
1939 57 80.9 46.0
1938 18 83.8 49.6
1937 49 81.5 46.4
1936 89 79.0 41.8
1935 40 85.2 44.9
1934 87 78.9 42.8
1933 101 74.0 42.4
1932 69 82.5 43.3
1931 74 81.0 43.7
1930 61 82.4 44.2
1929 105 76.1 38.9
1928 71 84.1 41.3
1927 102 73.8 42.4
1926 111 74.4 39.4
1925 86 76.8 45.2
1923 56 80.8 46.4
1922 50 83.2 44.6
1921 110 72.4 41.6
1920 80 76.9 46.5
1919 84 78.0 44.3
1918 43 79.4 49.1
1917 48 82.4 45.6
1916 97 77.8 40.6
1915 100 74.9 41.7
1914 95 76.8 42.1
1913 77 79.6 44.2
1912 109 72.9 41.2
1911 96 76.5 42.1
Weather Station Details
Years Station Coordinates
1940–2024 location
1911–1939 Meridian 1 W location