1991-2020 Degrees Fahrenheit 1 31.3 31.4 -0.1 66 42 1965 2012 2014 2016 normal 2 29.5 25.0 4.5 97 11 2014 2012 2015 2016 top-tenth 3 25.9 21.5 4.4 98 9 1912 2012 2016 2012 top-tenth 4 24.1 21.2 2.9 96 11 1979 2012 2015 2016 top-tenth 5 27.8 23.7 4.1 101 6 1979 2012 2015 2016 top-tenth 6 31.9 27.7 4.2 103 4 1979 2012 2015 2016 top-tenth 1931 7 36.5 32.5 4.0 103 3 1912 2012 2015 2016 top-tenth 8 40.7 36.9 3.8 102 3 1979 2012 2015 2016 top-tenth 9 44.1 40.6 3.5 102 3 1979 2012 2015 2016 top-tenth 10 46.6 43.3 3.3 103 2 1979 2012 2016 2016 top-tenth 2016 11 47.7 44.6 3.1 103 2 1979 2012 2016 2012 top-tenth 12 47.6 44.6 3.0 103 2 1951 2012 2016 2016 top-tenth 2016 18 42.7 39.0 3.7 103 1 1918,1979 2017 2016 2017 highest 24 47.6 44.6 3.0 101 1 1918,1952 2017 2016 2017 highest 36 46.2 44.6 1.6 96 3 1918 2013,2018 2016 2013 top-tenth 48 44.9 44.6 0.3 79 18 1970 1934,2013 2016 2014 top-third 2003,2020 60 45.1 44.6 0.5 83 12 1997 1935 2015 2016 top-third 1942,2009,2012