1991-2020 Degrees Fahrenheit 1 37.6 42.9 -5.3 6 69 1983 2002 1983 1982 bottom-tenth 2 32.1 39.1 -7.0 2 73 1964 2017 1964 1983 bottom-tenth 3 24.9 34.3 -9.4 1 74 1984 2017 1984 1983 lowest 4 18.9 30.0 -11.1 1 74 1984 2015 1984 1983 lowest 5 17.8 27.6 -9.8 1 72 1984 2018 1984 1983 lowest 6 19.4 28.1 -8.7 1 72 1984 2018 1984 1983 lowest 7 22.7 30.4 -7.7 1 72 1984 2018 1984 1983 lowest 8 27.0 33.6 -6.6 1 72 1984,1992 2018 1984 1983 lowest 1992 9 31.1 36.9 -5.8 2 71 1992 2018 1984 1983 bottom-tenth 10 34.5 39.8 -5.3 2 71 1992 2018 1973 1983 bottom-tenth 1973 11 36.5 41.7 -5.2 1 72 1984 2018 1984 1983 lowest 12 37.3 42.5 -5.2 1 72 1984 2018 1984 1983 lowest 18 34.1 37.7 -3.6 4 67 1993 2018 1980 1983 bottom-tenth 1965,1980 24 39.2 42.5 -3.3 2 69 1993 2018 1974 1983 bottom-tenth 1974 36 40.1 42.5 -2.4 6 63 1975,1993 2018 1977 1983 bottom-tenth 1973,1976,1985 48 40.8 42.3 -1.5 19 48 1976 2019 1980 1983 bottom-third 1978,1990 60 40.8 42.2 -1.4 21 44 1977 2020 1980 1983 bottom-third 1991