1901-2000 Degrees Fahrenheit 1 49.8 51.3 -1.5 42 88 1960 2012 1896 1898 bottom-third 2 40.6 47.2 -6.6 5 125 1960 2012 1899 1898 bottom-tenth 3 39.8 44.6 -4.8 8 122 1978 2012 1899 1898 bottom-tenth 4 39.3 43.8 -4.5 3 126 1978 1907 1899 1898 bottom-tenth 1979 5 40.7 45.0 -4.3 3 126 1978 2017 1899 1898 bottom-tenth 6 43.8 47.8 -4.0 2 127 1978 2017 1899 1898 bottom-tenth 1977 7 48.2 51.4 -3.2 3 126 1977 2017 1899 1898 bottom-tenth 8 52.0 54.9 -2.9 2 127 1977 2017 1899 1898 bottom-tenth 1918,1978 9 55.1 57.7 -2.6 3 126 1977 2017 1899 1898 bottom-tenth 1968 10 57.4 59.6 -2.2 4 125 1977 2017 1899 1898 bottom-tenth 11 58.7 60.4 -1.7 8 121 1977 2017 1899 1898 bottom-tenth 1980,1993,2014 12 58.6 60.4 -1.8 4 125 1977 2017 1899 1898 bottom-tenth 1984 18 55.5 56.2 -0.7 26 102 1978,1979,1980 2017 1899 1898 bottom-third 1903 24 60.1 60.4 -0.3 32 96 1978 2017 1899 1898 bottom-third 1912,1983,1998 36 60.9 60.4 0.5 83 44 1906,1979 2018 1899 1898 normal 1950,2004,2005 48 60.7 60.4 0.3 79 47 1980 2019 1899 1899 normal 1927,1932,1942,1944,1950,1954,1989,1999,2015 60 -99 60.4 -99 -99 -99 1980 2020 normal