1991-2020 Degrees Fahrenheit 1 52.7 57.3 -4.6 9 76 1976 1965 1976 1991 bottom-third 1947 2 60.1 62.7 -2.6 12 73 1976 2016 1980 1991 bottom-third 3 65.6 68.1 -2.5 12 73 1976 2016 1979 1991 bottom-third 2008 4 69.0 72.3 -3.3 3 82 1976 2016 1979 1991 bottom-tenth 1979 5 71.9 74.7 -2.8 8 77 1976 2011,2016 1979 1991 bottom-tenth 1950 6 73.1 75.9 -2.8 6 78 1976 2011 1979 1991 bottom-tenth 1968 7 73.0 75.7 -2.7 5 79 1976 1998 1979 1991 bottom-tenth 1967 8 72.1 74.6 -2.5 5 79 1976 2011 1983 1991 bottom-tenth 1974,1983 9 70.7 72.9 -2.2 10 74 1976 2011 1983 1991 bottom-third 1957,1993 10 69.2 70.9 -1.7 20 64 1940 2011,2016 1989 1991 bottom-third 1942,1969,1971,2014 11 67.2 68.9 -1.7 23 61 1940 2016 1989 1991 bottom-third 1948,1988,1997 12 66.0 67.3 -1.3 35 49 1940 2016 1989 1991 normal 1943,1997 18 68.7 70.2 -1.5 25 58 1968 2016 1988 1991 bottom-third 1970,1974,1987,1988 24 66.2 67.3 -1.1 45 38 1979 2017 1989 1991 normal 1950,2014 36 66.5 67.3 -0.8 53 29 1961 2017,2018 1991 1987 normal 1987,1996 48 66.3 67.2 -0.9 49 32 1961 2018 1991 1991 normal 1965,1991 60 66.2 67.2 -1.0 47 33 1962 2019,2020 1991 1991 normal 1953,1966,1989,1990,1991,1996,1997