1991-2020 Degrees Fahrenheit 1 10.3 25.3 -15.0 2 120 1918 2006 1912 1911 bottom-tenth 2 20.8 28.0 -7.2 10 110 1918 1932 1904 1911 bottom-tenth 3 24.7 32.4 -7.7 4 115 1977 2002 1904 1911 bottom-tenth 4 31.0 37.6 -6.6 4 114 1977 1932 1904 1911 bottom-tenth 5 37.8 43.0 -5.2 4 114 1977 1932 1904 1911 bottom-tenth 6 43.1 47.8 -4.7 4 114 1977 1932 1904 1911 bottom-tenth 1930 7 47.5 51.5 -4.0 5 113 1977 1932 1904 1911 bottom-tenth 1963 8 50.3 53.8 -3.5 6 112 1918 1932 1904 1911 bottom-tenth 1925 9 52.1 54.5 -2.4 20 98 1918 1932 1911 1909 bottom-third 1970 10 51.4 54.0 -2.6 14 103 1918 1932 1910 1911 bottom-third 1926,1938,1963 11 49.8 52.5 -2.7 15 102 1918 2013 1910 1911 bottom-third 12 48.1 50.5 -2.4 22 94 1918 2013 1910 1911 bottom-third 1994 18 47.2 49.6 -2.4 13 97 1918 2017 1908 1911 bottom-third 1926,1963,1980 24 48.4 50.5 -2.1 20 88 1918 2013 1911 1910 bottom-third 1909,1917,1938,1964,1998 36 48.0 50.5 -2.5 9 92 1918 2013 1910 1911 bottom-tenth 1908,1910,1963 48 48.5 50.5 -2.0 16 80 1918 2019,2020 1911 1909 bottom-third 1909,1962 60 48.2 50.4 -2.2 8 83 1918 2020,2021 1910 1911 bottom-tenth 1910,1982,1983