1991-2020 Degrees Fahrenheit 1 74.2 74.6 -0.4 40 36 1972 2010 1968 1970 normal 2 68.6 70.7 -2.1 14 62 1992 2018 1968 1970 bottom-third 1988,2005 3 64.8 66.7 -1.9 14 62 1997 2010 1967 1970 bottom-third 1974,1976 4 59.9 62.3 -2.4 10 66 1960 2012 1966 1970 bottom-third 1975 5 56.0 58.2 -2.2 14 62 1958 2012 1967 1970 bottom-third 1950,1965 6 52.6 54.9 -2.3 12 64 1958 2012 1970 1968 bottom-third 1972 7 51.0 53.1 -2.1 16 59 1978 2012 1970 1968 bottom-third 1951,1962,1984 8 50.6 52.6 -2.0 19 56 1978 2012 1970 1968 bottom-third 9 51.8 53.4 -1.6 26 49 1958,1978 2012 1970 1967 normal 1965,1967,1980,1989,2014 10 54.1 55.1 -1.0 37 38 1958 2017 1970 1957 normal 1987 11 56.0 57.1 -1.1 37 38 1958,1977 2017 1970 1957 normal 1981 12 57.8 58.8 -1.0 34 41 1977 2017 1970 1959 normal 1972 18 56.0 57.6 -1.6 24 51 1961,1963,1979 2012 1970 1960 bottom-third 1951,1956,1983 24 57.0 58.8 -1.8 13 61 1978 2017 1970 1967 bottom-third 1967,1983 36 57.0 58.8 -1.8 11 62 1970,1979 2018 1970 1967 bottom-third 1967,1978 48 56.8 58.8 -2.0 5 67 1980 2020 1970 1969 bottom-tenth 1961,1963,1965,1968,1969 60 56.9 58.7 -1.8 9 62 1967,1970 2020 1970 1963 bottom-third