1991-2020 Degrees Fahrenheit 1 17.1 25.3 -8.2 13 109 1918 2006 1963 1969 bottom-third 2 22.4 28.0 -5.6 22 98 1918 1932 1963 1969 bottom-third 3 27.4 32.4 -5.0 14 105 1977 2002 1963 1969 bottom-third 4 33.4 37.6 -4.2 14 104 1977 1932 1963 1969 bottom-third 5 39.5 43.0 -3.5 17 101 1977 1932 1963 1969 bottom-third 1920,1927,1984 6 45.1 47.8 -2.7 22 96 1977 1932 1963 1969 bottom-third 1945,2001 7 49.1 51.5 -2.4 25 93 1977 1932 1968 1969 bottom-third 1920,1945,1979 8 51.1 53.8 -2.7 19 99 1918 1932 1963 1969 bottom-third 2001 9 52.1 54.5 -2.4 20 98 1918 1932 1968 1969 bottom-third 1912 10 51.9 54.0 -2.1 24 93 1918 1932 1968 1969 bottom-third 1973,1993 11 50.2 52.5 -2.3 19 98 1918 2013 1963 1969 bottom-third 1916,1926,1994 12 48.4 50.5 -2.1 30 86 1918 2013 1968 1969 bottom-third 1906,1981,1990 18 47.9 49.6 -1.7 36 74 1918 2017 1969 1969 bottom-third 1898,1961,1969 24 48.7 50.5 -1.8 36 72 1918 2013 1969 1967 bottom-third 1910,1971 36 48.5 50.5 -2.0 20 81 1918 2013 1968 1969 bottom-third 1909,1961,1964,1968,1977,1978 48 48.6 50.5 -1.9 19 77 1918 2019,2020 1964 1969 bottom-third 1915,1963,1971,1983 60 48.6 50.4 -1.8 18 73 1918 2020,2021 1965 1969 bottom-third 1915,1916,1917,1965