1991-2020 Degrees Fahrenheit 1 41.4 43.1 -1.7 35 94 1994 1926 1985 1991 bottom-third 2 49.2 48.7 0.5 87 40 1994 1933 1989 1991 top-third 1914,1949,1962,1970 3 54.9 54.6 0.3 98 29 1982 2012 1989 1991 top-third 1910 4 59.8 59.6 0.2 103 23 1982 2012 1990 1991 top-third 1950 5 62.3 62.9 -0.6 93 33 1982 2012 1989 1991 top-third 6 63.3 63.9 -0.6 97 29 1982 2021 1990 1991 top-third 1987 7 63.7 63.2 0.5 108 17 1916 2021 1991 1988 top-third 8 62.9 61.7 1.2 116 9 1896 2021 1991 1992 top-tenth 9 61.3 59.9 1.4 117 8 1912 2014 1991 1934 top-tenth 1934,2007 10 59.5 57.9 1.6 117 7 1897 2014 1991 1934 top-tenth 1934 11 57.4 56.0 1.4 114 10 1897 2014 1991 1934 top-tenth 12 55.5 54.2 1.3 114 10 1897 2015 1991 1934 top-tenth 2018 18 58.3 57.4 0.9 109 12 1898 2015 1991 1934 top-tenth 24 54.1 54.2 -0.1 97 23 1898 2015 1991 1988 top-third 36 53.9 54.1 -0.2 94 23 1898 2016,2017 1991 1988 top-third 48 53.4 54.1 -0.7 78 36 1913 2017 1991 1990 top-third 60 53.7 54.1 -0.4 90 22 1975 2018 1991 1990 top-third 1940,1942,1990,2011