1991-2020 Degrees Fahrenheit 1 55.6 55.8 -0.2 42 33 1976 1985 1980 1979 normal 2 59.1 60.9 -1.8 15 60 1976 1985 1980 1979 bottom-third 1950 3 64.0 66.0 -2.0 8 67 1967 1985 1976 1980 bottom-third 1968,1995 4 67.4 69.9 -2.5 3 72 1967 2016 1976 1980 bottom-tenth 5 70.4 72.4 -2.0 5 70 1967 2016 1976 1980 bottom-tenth 6 72.3 73.6 -1.3 16 59 1967 2016 1979 1980 bottom-third 1964,1979 7 72.0 73.4 -1.4 10 65 1967 2016 1976 1980 bottom-third 8 71.5 72.3 -0.8 21 54 1967,1976 2016 1979 1980 bottom-third 1964,1983,1984 9 69.5 70.7 -1.2 14 61 1976 2016 1976 1980 bottom-third 1961,1974 10 67.5 68.7 -1.2 16 59 1967 2016 1979 1980 bottom-third 1975,1997 11 65.2 66.8 -1.6 9 65 1966 2019 1979 1980 bottom-third 1992 12 63.7 65.5 -1.8 7 67 1966,1969 2016 1979 1980 bottom-tenth 1961,1970,1979,1996,2014 18 67.1 68.2 -1.1 20 53 1968 2017 1977 1980 bottom-third 1965,1982 24 64.3 65.4 -1.1 19 53 1967 2017 1980 1975 bottom-third 1984,1993 36 64.1 65.4 -1.3 11 59 1968,1969 2018 1980 1980 bottom-third 1964,1980 48 64.0 65.3 -1.3 8 60 1969 2019 1979 1980 bottom-third 1964,1972,1978 60 64.1 65.3 -1.2 11 55 1970 2020 1980 1978 bottom-third 1965,1982