1901-2000 Degrees Fahrenheit 1 16.57 22.60 -6.03 3 126 1909 2015 1983 1988 bottom-tenth 2 23.80 26.64 -2.84 6 123 1976 2015 1976 1988 bottom-tenth 3 29.59 31.56 -1.97 8 121 1976 2015 1976 1988 bottom-tenth 4 34.99 36.65 -1.66 9 120 1976 2015 1976 1988 bottom-tenth 5 39.79 41.13 -1.34 9 120 1976 2015 1976 1988 bottom-tenth 6 43.40 44.36 -0.96 10 119 1976 2021 1976 1988 bottom-tenth 7 45.15 45.97 -0.82 13 116 1976 2021 1985 1988 bottom-tenth 1985 8 45.47 46.16 -0.69 20 109 1976 2015 1976 1988 bottom-third 9 44.84 45.32 -0.48 24 105 1917 2015 1976 1988 bottom-third 1972 10 43.45 43.79 -0.34 33 96 1917 2015 1976 1988 bottom-third 11 41.21 41.88 -0.67 16 113 1917 2016 1976 1988 bottom-third 12 39.69 40.04 -0.35 31 98 1917 2016 1985 1988 bottom-third 1907,1967 18 41.42 41.48 -0.06 58 70 1917 2016 1985 1988 normal 24 39.88 40.03 -0.15 50 78 1917 2017 1980 1988 normal 1962 36 40.36 40.02 0.34 78 49 1918 2017 1985 1988 normal 1922,1942 48 40.70 40.01 0.69 94 32 1919 2018 1988 1987 top-third 1995 60 40.47 40.00 0.47 84 41 1920 2019 1986 1988 top-third