1991-2020 Degrees Fahrenheit 1 42.5 45.0 -2.5 80 45 1948 2017 2002 2004 normal 2 40.3 40.1 0.2 105 20 1933 2017 2004 2001 top-third 3 39.2 36.0 3.2 119 6 1917 2015,2017 2004 1999 top-tenth 4 36.5 34.0 2.5 115 9 1917 2015 2004 2003 top-tenth 1996,2000 5 36.9 35.1 1.8 113 11 1917 2017 2004 2003 top-tenth 1907 6 39.6 38.1 1.5 113 11 1917 2017 2004 2000 top-tenth 7 43.2 42.3 0.9 112 12 1917 2017 2004 2000 top-tenth 1978 8 47.1 46.5 0.6 111 13 1917 2017 2004 2003 top-third 2003,2021 9 50.6 50.1 0.5 108 16 1917 2017 2004 2003 top-third 2006 10 52.9 52.4 0.5 112 12 1917 2017 2004 2003 top-tenth 1981,1986,2000,2019 11 53.9 53.3 0.6 113 11 1917 2017 2004 2003 top-tenth 1986,2001 12 53.8 53.2 0.6 113 11 1913 2017 2004 2003 top-tenth 1986 18 48.5 48.2 0.3 108 15 1913 2018 2002 2004 top-third 1996,1999,2015,2021 24 53.7 53.2 0.5 113 10 1913 2018 2001 2004 top-tenth 2015 36 54.0 53.1 0.9 118 4 1914 2019 2004 2003 top-tenth 2003 48 53.9 53.1 0.8 117 4 1920 2018 2004 2004 top-tenth 2004,2017,2021 60 53.9 53.0 0.9 114 6 1917 2019 2004 2005 top-tenth 2017