1991-2020 Degrees Fahrenheit 1 31.9 27.7 4.2 115 12 1904 1998 1986 1984 top-tenth 2 29.8 27.2 2.6 111 14 1912 1998 1986 1983 top-third 1983 3 30.7 28.8 1.9 110 15 1904 2002 1986 1983 top-third 4 32.4 31.8 0.6 99 26 1904 2002 1986 1983 top-third 1939 5 36.1 35.8 0.3 99 26 1918 1932 1986 1983 top-third 2020,2021 6 40.6 40.4 0.2 97 28 1918 1932 1986 1983 top-third 2018 7 44.4 44.8 -0.4 91 34 1918 1932,2017 1986 1983 top-third 8 48.1 48.2 -0.1 96 29 1918 1932 1986 1983 top-third 1931,2004 9 50.0 50.3 -0.3 93 32 1918 1932 1986 1983 top-third 1922,1953,1988,2004 10 51.0 51.0 0.0 98 26 1918 2017 1986 1983 top-third 1922,1995 11 50.9 50.7 0.2 102 21 1918 2017 1986 1983 top-third 1956,1983 12 49.8 49.4 0.4 102 19 1918 2017 1986 1954 top-third 1922,1989 18 46.1 46.4 -0.3 88 31 1918 2017 1986 1984 top-third 1956,2019 24 49.2 49.4 -0.2 93 23 1918 2013 1986 1955 top-third 1922,1955,1993,2009,2019 36 48.7 49.4 -0.7 77 34 1918 2013 1986 1976 top-third 1923 48 48.6 49.4 -0.8 71 36 1919,1927 2002,2013 1986 1976 normal 1976 60 48.8 49.4 -0.6 71 33 1920 2002 1986 1957 top-third 1995