1991-2020 Degrees Fahrenheit 1 74.2 76.0 -1.8 28 74 1974 1998 1932 1933 bottom-third 2009 2 81.1 80.1 1.0 73 28 1974 1954 1933 1931 top-third 1990 3 83.7 81.6 2.1 88 13 1950 2011 1933 1934 top-third 4 84.0 81.3 2.7 92 9 1989 2011 1933 1934 top-tenth 5 81.7 79.4 2.3 92 9 1992 2011 1933 1934 top-tenth 2018 6 78.7 76.6 2.1 92 9 1973 2011 1933 1934 top-tenth 2000 7 74.6 73.5 1.1 87 14 1975 2011 1933 1925 top-third 1953 8 70.9 70.1 0.8 82 18 1975 2011 1933 1930 top-third 1946,1977,2017 9 67.8 67.1 0.7 83 17 1979 2011 1933 1933 top-third 1933,1986,2018 10 65.7 64.7 1.0 90 10 1979 2011 1933 1934 top-tenth 1939,1953,1998 11 64.7 63.6 1.1 91 8 1973 2011 1933 1934 top-tenth 12 64.8 63.7 1.1 91 8 1973 2011 1933 1934 top-tenth 1954 18 69.0 68.0 1.0 90 9 1973 2012 1933 1934 top-tenth 1954,2013,2016 24 64.0 63.7 0.3 79 19 1979 2012 1933 1934 top-third 1964,2007 36 63.8 63.7 0.1 77 20 1979 2013 1933 1934 top-third 1935 48 63.4 63.7 -0.3 68 28 1979 2012 1933 1934 top-third 1937,1939,2021 60 63.2 63.6 -0.4 59 36 1979 2012 1933 1934 normal 1940,1942,1959