Boise September 21 Weather Records

Daily averages and all-time records for weather in Boise, Idaho for the date of September 21.
September 21 All-Time Records
1911–2024
Highest temperature 95 °F 1967
Lowest temperature 29 °F 1914
Lowest daily high 52 °F 1968
Highest daily low 62 °F 2014
Most precipitation 0.15 inches 2016
Most snow none -
September 21 Average Weather
1991–2020 1
Average high 77.3 °F
Average low 50.2 °F
Chance precipitation 14.6%
Chance snow 0%
Boise September 21 Weather by Year
Year High (°F) Low (°F) Precip. (inches) Snow (inches)
2023 66 43 0.00 0.0
2022 74 53 0.07 0.0
2021 77 47 0.00 0.0
2020 89 56 0.00 0.0
2019 71 45 0.00 0.0
2018 83 49 0.00 0.0
2017 58 47 0.09 0.0
2016 69 48 0.15 0.0
2015 83 55 0.00 0.0
2014 83 62 0.00 0.0
2013 73 56 0.00 0.0
2012 79 53 0.00 0.0
2011 84 51 0.00 0.0
2010 76 51 0.00 0.0
2009 73 43 0.00 0.0
2008 63 49 0.02 0.0
2007 76 45 0.00 0.0
2006 64 49 0.08 0.0
2005 75 54 0.00 0.0
2004 63 36 0.00 0.0
2003 77 46 0.00 0.0
2002 73 39 0.00 0.0
2001 84 51 0.00 0.0
2000 70 47 0.00 0.0
1999 89 56 0.00 0.0
1998 69 47 0.00 0.0
1997 74 47 0.00 0.0
1996 66 43 0.00 0.0
1995 67 40 0.00 0.0
1994 86 45 0.00 0.0
1993 65 30 0.00 0.0
1992 83 51 0.00 0.0
1991 68 41 0.00 0.0
1990 79 42 0.00 0.0
1989 75 44 0.00 0.0
1988 69 38 0.00 0.0
1987 85 51 0.00 0.0
1986 62 36 0.00 0.0
1985 71 50 0.00 0.0
1984 59 42 0.00 0.0
1983 71 34 0.00 0.0
1982 74 45 0.00 0.0
1981 67 39 0.00 0.0
1980 60 41 0.00 0.0
1979 88 56 0.00 0.0
1978 70 46 0.00 0.0
1977 62 42 0.00 0.0
1976 78 58 0.00 0.0
1975 81 49 0.00 0.0
1974 83 54 0.00 0.0
1973 70 46 0.00 0.0
1972 82 54 0.02 0.0
1971 67 38 0.00 0.0
1970 61 43 0.00 0.0
1969 66 44 0.00 0.0
1968 52 41 0.07 0.0
1967 95 60 0.00 0.0
1966 91 58 0.00 0.0
1965 73 47 0.00 0.0
1964 68 36 0.00 0.0
1963 80 59 0.04 0.0
1962 81 55 0.00 0.0
1961 57 38 0.00 0.0
1960 68 38 0.00 0.0
1959 61 38 0.00 0.0
1958 81 41 0.00 0.0
1957 74 43 0.00 0.0
1956 61 40 0.00 0.0
1955 61 37 0.00 0.0
1954 93 49 0.00 0.0
1953 84 53 0.00 0.0
1952 85 54 0.00 0.0
1951 68 44 0.00 0.0
1950 81 55 0.00 0.0
1949 79 43 0.00 0.0
1948 88 51 0.00 0.0
1947 76 47 0.00 0.0
1946 65 48 0.00 0.0
1945 58 42 0.13 0.0
1944 68 50 0.00 0.0
1943 79 48 0.00 0.0
1942 80 45 0.00 0.0
1941 67 35 0.00 0.0
1940 70 48 0.02 0.0
1939 89 50 0.00 0.0
1938 82 52 0.00 0.0
1937 82 47 0.00 0.0
1936 93 43 0.00 0.0
1935 88 44 0.00 0.0
1934 78 40 0.00 0.0
1933 68 38 0.00 0.0
1932 72 32 0.00 n/a
1931 65 40 0.00 n/a
1930 90 43 0.00 n/a
1929 66 41 0.04 n/a
1928 80 36 0.00 n/a
1927 85 45 0.00 0.0
1926 67 36 0.00 0.0
1925 71 38 0.00 0.0
1924 81 42 0.00 0.0
1923 81 50 0.00 0.0
1922 90 50 0.00 0.0
1921 74 38 0.00 0.0
1920 66 39 0.00 0.0
1919 70 40 0.00 0.0
1918 87 52 0.00 0.0
1917 85 54 0.00 0.0
1916 85 38 0.00 0.0
1915 84 45 0.00 0.0
1914 69 29 0.00 0.0
1913 73 40 0.05 0.0
1912 71 36 0.00 0.0
1911 82 38 0.00 0.0
What's the all-time high for Boise on 9/21?
For the date of Sep 21, the highest temperature ever reached in Boise history is 95 °F which happened in 1967.
Highest Temperatures in Boise on September 21
Rank Temperature Year
1 95 °F 1967
2 93 °F 1954
2 93 °F 1936
4 91 °F 1966
5 90 °F 1930
5 90 °F 1922
7 89 °F 1999
7 89 °F 1939
7 89 °F 2020
10 88 °F 1948
10 88 °F 1979
10 88 °F 1935
What's the all-time low for Boise on 9/21?
For the date of Sep 21, the lowest temperature ever reached in Boise history is 29 °F which happened in 1914.
Lowest Temperatures in Boise on September 21
Rank Temperature Year
1 29 °F 1914
2 30 °F 1993
3 32 °F 1932
4 34 °F 1983
5 35 °F 1941
6 36 °F 1986
6 36 °F 1928
6 36 °F 2004
6 36 °F 1926
6 36 °F 1964
6 36 °F 1912
Lowest High Temperatures in Boise on September 21
Rank Temperature Year
1 52 °F 1968
2 57 °F 1961
3 58 °F 1945
3 58 °F 2017
5 59 °F 1984
6 60 °F 1980
7 61 °F 1956
7 61 °F 1955
7 61 °F 1959
7 61 °F 1970
What's the most it has ever rained in Boise on 9/21?
For the date of Sep 21, the most precipitation ever recorded in Boise history is 0.15 inches which happened in 2016.
All-Time Most Precipitation in Boise on September 21
Rank Precipitation Year
1 0.15 inches 2016
2 0.13 inches 1945
3 0.09 inches 2017
4 0.08 inches 2006
5 0.07 inches 2022
5 0.07 inches 1968
7 0.05 inches 1913
8 0.04 inches 1963
8 0.04 inches 1929
10 0.02 inches 1972
10 0.02 inches 2008
10 0.02 inches 1940
Weather Station Details
Years Station Coordinates
1940–2024 location
1911–1939 Meridian 1 W location
Notes
1: Daily averages are a moving average which includes 14 days before and after the date.
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