1991-2020 Degrees Fahrenheit 1 51.4 59.7 -8.3 2 86 1939 2016 1939 1963 bottom-tenth 2 50.1 58.1 -8.0 2 84 1949 2014,2015 1949 1963 bottom-tenth 3 51.4 57.2 -5.8 2 84 1949 2015 1949 1963 bottom-tenth 4 54.6 59.1 -4.5 5 80 1949 2018 1960 1963 bottom-tenth 1960 5 59.3 62.7 -3.4 13 71 1949 2018 1960 1963 bottom-third 1979 6 64.0 67.0 -3.0 19 65 1949 2018 1962 1963 bottom-third 7 67.6 70.8 -3.2 16 68 1942 2018 1962 1963 bottom-third 1945,1979 8 70.9 73.9 -3.0 16 68 1942 2021 1962 1963 bottom-third 1956 9 72.4 75.8 -3.4 12 72 1942 2018,2021 1960 1963 bottom-third 1960,1969 10 73.3 76.4 -3.1 16 67 1942 2021 1962 1963 bottom-third 1962 11 72.9 76.0 -3.1 14 68 1942 2021 1958 1963 bottom-third 1943,1954,1976,1985 12 72.0 75.2 -3.2 15 67 1942 2018 1958 1963 bottom-third 1958,1971 18 69.9 72.5 -2.6 22 58 1945 2018 1963 1960 bottom-third 1969,1977,1980,1984 24 72.5 75.2 -2.7 24 54 1943 2018 1963 1963 bottom-third 1963 36 72.4 75.2 -2.8 22 54 1944 2018 1958 1963 bottom-third 48 72.6 75.2 -2.6 23 51 1945 2018 1963 1963 bottom-third 1963,1978 60 72.5 75.1 -2.6 21 51 1966 2018 1960 1963 bottom-third 1978