1991-2020 Degrees Fahrenheit 1 44.8 49.5 -4.7 9 67 2000 2015 1963 1967 bottom-third 2 49.0 52.7 -3.7 9 66 1950 2015 1963 1967 bottom-third 3 54.2 57.1 -2.9 7 68 1976 2015 1963 1967 bottom-tenth 4 59.2 61.9 -2.7 8 67 1976 2015,2016 1967 1966 bottom-third 5 63.8 65.8 -2.0 10 65 1976 2016 1967 1966 bottom-third 1992 6 66.8 68.6 -1.8 11 64 1976 2016 1967 1966 bottom-third 1974 7 68.5 70.1 -1.6 15 60 1967,1976 2016 1967 1964 bottom-third 1981 8 68.8 70.5 -1.7 8 67 1976 1998,2016 1967 1966 bottom-third 1966,1969,1974,1975 9 68.5 69.8 -1.3 14 61 1976 2015 1967 1965 bottom-third 1969 10 67.1 68.6 -1.5 12 63 1976 2015,2016 1967 1965 bottom-third 1981,1996 11 64.8 67.0 -2.2 1 74 1968 2016 1968 1967 lowest 12 63.0 65.4 -2.4 1 73 1968 2019 1968 1967 lowest 18 63.7 66.5 -2.8 1 72 1968 2017 1968 1967 lowest 24 63.3 65.4 -2.1 2 70 1969 2017,2020 1968 1967 bottom-tenth 36 63.3 65.4 -2.1 1 69 1968,1969 2019 1968 1967 lowest 1969 48 63.5 65.3 -1.8 2 66 1969 2019 1968 1967 bottom-tenth 1970 60 63.7 65.3 -1.6 3 63 1969,1970 2019,2020 1968 1967 bottom-tenth