1991-2020 Degrees Fahrenheit 1 57.7 59.7 -2.1 52 40 1978 2017 1960 1957 normal 2 53.4 57.8 -4.4 22 69 1978 2017 1960 1959 bottom-third 1984 3 53.2 57.7 -4.5 13 78 1978 2017 1958 1960 bottom-third 1958 4 55.8 59.3 -3.5 17 74 1977 2017 1960 1959 bottom-third 1968 5 59.4 62.2 -2.8 23 63 1977 2017 1960 1957 bottom-third 1937,1980 6 62.8 65.5 -2.7 21 65 1977 2017 1960 1957 bottom-third 1988 7 65.7 68.4 -2.7 17 69 1977 2017 1960 1959 bottom-third 8 68.1 70.5 -2.4 16 69 1977 2017 1960 1959 bottom-third 1941,1953 9 69.8 72.0 -2.2 18 67 1977 2017 1960 1959 bottom-third 1953,1963 10 70.3 72.7 -2.4 15 70 1977 2017 1960 1959 bottom-third 1937,1953,1964 11 70.4 72.6 -2.2 19 65 1977 2017 1960 1959 bottom-third 1948 12 69.3 72.0 -2.7 9 75 1977 2017 1960 1959 bottom-third 1948,1980 18 66.8 69.8 -3.0 5 76 1978 2017 1941 1960 bottom-tenth 1980,1984 24 69.3 71.9 -2.6 4 76 1978 2017 1942 1960 bottom-tenth 1942,1979,1980 36 69.5 72.0 -2.5 6 70 1979 2018 1942 1960 bottom-tenth 1962,1981 48 69.5 71.9 -2.4 5 67 1980 2019 1961 1960 bottom-tenth 1963 60 70.0 72.0 -2.0 19 50 1980,1981 2020 1961 1960 bottom-third 1966,1968,1972