1991-2020 Degrees Fahrenheit 1 64.8 66.9 -2.1 22 54 1967 2018 1984 1987 bottom-third 2 60.8 62.8 -2.0 16 60 1961 2019 1984 1987 bottom-third 3 56.8 58.2 -1.4 28 48 1960 2012 1984 1987 normal 1970 4 52.5 54.1 -1.6 30 46 1958 2012 1987 1986 normal 1962,1984,2014 5 48.4 51.0 -2.6 12 64 1958,1978 2012 1979 1987 bottom-third 1996 6 47.5 49.5 -2.0 22 53 1978 2012 1987 1987 bottom-third 1987,1993,2014 7 48.0 49.4 -1.4 31 44 1978 2012 1987 1986 normal 8 48.6 50.7 -2.1 16 59 1978 2012 1984 1987 bottom-third 1968,1984,1994 9 51.0 52.9 -1.9 19 56 1958,1977,1978 2017 1984 1987 bottom-third 1993,1994,1997,2014 10 53.9 55.3 -1.4 30 45 1958,1977 2017 1987 1987 normal 1987 11 56.3 57.4 -1.1 32 43 1977 2012,2017 1987 1987 normal 1962,1971,1981,1987 12 58.0 58.8 -0.8 38 37 1977 2012 1987 1986 normal 18 54.5 55.7 -1.2 32 42 1970 2017 1987 1987 normal 1987 24 57.9 58.8 -0.9 34 40 1978 2017 1984 1987 normal 2014 36 58.1 58.8 -0.7 40 33 1970,1979 2018,2019 1985 1987 normal 48 58.4 58.7 -0.3 47 25 1980 2019,2020 1987 1988 normal 60 58.2 58.7 -0.5 42 29 1970 2020 1987 1976 normal 1957,1976,1989,1999