1991-2020 Degrees Fahrenheit 1 54.7 49.5 5.2 69 7 2000 2015 1970 1971 top-tenth 2 54.4 52.7 1.7 58 17 1950 2015 1970 1971 top-third 3 58.1 57.1 1.0 54 21 1976 2015 1970 1971 top-third 2018 4 62.8 61.9 0.9 58 17 1976 2015,2016 1970 1971 top-third 2017 5 66.3 65.8 0.5 56 19 1976 2016 1970 1971 top-third 1951,1970 6 68.4 68.6 -0.2 45 30 1976 2016 1969 1971 normal 7 69.4 70.1 -0.7 30 45 1967,1976 2016 1969 1971 normal 1957,1961,1994,2009 8 69.4 70.5 -1.1 20 55 1976 1998,2016 1969 1971 bottom-third 1961,2003 9 68.8 69.8 -1.0 20 55 1976 2015 1969 1971 bottom-third 1996 10 67.6 68.6 -1.0 25 50 1976 2015,2016 1969 1971 bottom-third 1963 11 65.7 67.0 -1.3 20 55 1968 2016 1969 1971 bottom-third 12 64.6 65.4 -0.8 30 44 1968 2019 1970 1971 normal 1987 18 66.3 66.5 -0.2 46 27 1968 2017 1971 1957 normal 24 64.6 65.4 -0.8 30 42 1969 2017,2020 1971 1958 normal 1994 36 64.5 65.4 -0.9 23 47 1968,1969 2019 1971 1959 bottom-third 1982 48 64.2 65.3 -1.1 12 56 1969 2019 1971 1965 bottom-third 1961,1965,1980 60 63.9 65.3 -1.4 6 60 1969,1970 2019,2020 1971 1966 bottom-tenth 1979