1991-2020 Degrees Fahrenheit 1 31.0 28.3 2.7 100 25 1978 2017 1951 1938 top-third 2 29.2 26.8 2.4 103 18 1912 2017 1951 1949 top-third 1944,1949 3 28.2 28.1 0.1 84 35 1904 1932 1951 1950 top-third 1944,1966 4 29.1 31.3 -2.2 41 77 1904 1932 1951 1950 normal 5 34.0 35.7 -1.7 44 73 1904 1932 1951 1950 normal 1944,1981 6 38.5 40.6 -2.1 36 81 1977 1932 1951 1950 bottom-third 7 42.7 45.0 -2.3 25 92 1977 1932 1951 1950 bottom-third 1897,2001,2009 8 46.3 48.6 -2.3 20 97 1977 1932 1951 1950 bottom-third 1899,1920,1997 9 48.6 51.0 -2.4 19 98 1904 1932 1951 1950 bottom-third 2001,2015 10 49.8 51.9 -2.1 23 94 1918 1932 1951 1950 bottom-third 1993 11 49.4 51.7 -2.3 18 98 1918 1932 1951 1950 bottom-third 1930,1993,2014 12 48.3 50.5 -2.2 20 96 1918 2017 1951 1950 bottom-third 1916,1938 18 44.8 47.2 -2.4 15 94 1918 2017 1927 1951 bottom-third 24 47.8 50.5 -2.7 4 104 1918 2017 1918 1951 bottom-tenth 1979,1980 36 48.7 50.5 -1.8 18 83 1918 2018 1927 1951 bottom-third 1908,1913,1964 48 49.1 50.5 -1.4 28 67 1980 2019 1927 1935 bottom-third 1914,1915,1953,1983,1996 60 -99 50.4 -99 -99 -99 1981 2020 normal