1901-2000 Degrees Fahrenheit 1 31.80 33.82 -2.02 33 97 1936 1954 1993 2009 bottom-third 2 31.24 31.97 -0.73 40 90 1979 2017 1994 2009 bottom-third 3 30.70 32.23 -1.53 22 107 1979 2016 1985 2009 bottom-third 4 34.49 34.60 -0.11 52 77 1979 2000 2001 2009 normal 1945 5 37.69 38.51 -0.82 30 99 1899 2017 2001 2009 bottom-third 6 42.47 42.90 -0.43 37 92 1899 2016 2001 2009 bottom-third 7 46.67 47.07 -0.40 35 94 1899 2017 2001 2009 bottom-third 8 49.92 50.39 -0.47 30 99 1899 2017 1994 2009 bottom-third 9 51.99 52.40 -0.41 34 95 1977 2017 1994 2009 bottom-third 10 52.95 53.18 -0.23 40 89 1918,1977 2017 1994 2009 bottom-third 11 52.77 52.98 -0.21 37 92 1918 2017 1994 2009 bottom-third 12 51.94 52.02 -0.08 55 74 1918 2017 1997 2009 normal 1960,1997 18 49.23 48.97 0.26 73 55 1918 2017 1997 2009 normal 24 52.24 52.01 0.23 73 55 1918 2017 1997 2009 normal 1947 36 52.74 52.00 0.74 96 31 1918 2018 1998 2009 top-third 48 52.91 51.99 0.92 102 24 1918 2019 1999 2009 top-third 60 53.10 51.98 1.12 105 20 1918 2020 2001 2009 top-third