1901-2000 Degrees Fahrenheit 1 56.0 59.3 -3.3 20 109 1915 2020 1971 1977 bottom-third 2 49.8 56.1 -6.3 2 127 2010 1945 1978 1977 bottom-tenth 3 47.0 54.1 -7.1 1 128 1978 1950 1978 1977 lowest 4 47.5 53.4 -5.9 1 127 1978 2017 1978 1977 lowest 5 49.8 54.2 -4.4 2 126 1977 2017 1977 1976 bottom-tenth 6 52.1 56.4 -4.3 2 126 1977 2017 1977 1976 bottom-tenth 7 55.8 59.4 -3.6 2 126 1977 2017 1977 1976 bottom-tenth 8 58.9 62.1 -3.2 2 126 1977 2017 1977 1976 bottom-tenth 9 61.5 64.2 -2.7 3 125 1977 2017 1977 1976 bottom-tenth 10 63.5 65.8 -2.3 3 125 1977 2017 1977 1976 bottom-tenth 11 64.5 66.5 -2.0 3 125 1977 2017,2020 1977 1976 bottom-tenth 12 64.8 66.5 -1.7 6 122 1977 2017,2020 1977 1976 bottom-tenth 18 60.4 63.1 -2.7 1 126 1978 2017 1978 1977 lowest 24 64.1 66.5 -2.4 1 126 1978 2017 1978 1977 lowest 36 64.8 66.5 -1.7 1 125 1978,1979 2018 1978 1977 lowest 1979 48 65.1 66.5 -1.4 2 123 1980 2020 1970 1977 bottom-tenth 1970,1979 60 65.7 66.5 -0.8 10 114 1981 2020 1972 1977 bottom-tenth 1964,1967