1991-2020 Degrees Fahrenheit 1 67.1 64.2 2.9 83 10 1976 1973 1930 1931 top-third 2 71.5 69.0 2.5 83 5 1976 2016 1930 1931 top-tenth 2020 3 74.8 73.3 1.5 81 7 1976 2016 1930 1931 top-tenth 4 76.5 76.5 0.0 70 18 1976 2016 1930 1931 top-third 2003 5 78.1 78.3 -0.2 68 19 1976 2016 1931 1931 top-third 6 78.6 79.2 -0.6 57 30 1976 2016 1931 1931 normal 1986,1994,1996,2008 7 77.5 79.1 -1.6 25 62 1976 1998 1931 1931 bottom-third 1993 8 75.9 78.2 -2.3 11 75 1976 2011 1931 1931 bottom-third 1968,1971 9 73.7 76.8 -3.1 5 81 1976 2011 1931 1931 bottom-tenth 1970 10 72.2 75.1 -2.9 9 76 1940 2017 1931 1931 bottom-third 1960 11 70.4 73.3 -2.9 10 74 1940 2017 1931 1931 bottom-third 1961 12 68.8 72.0 -3.2 7 77 1940 2017 1931 1931 bottom-tenth 1970,1978 18 -99 74.4 -99 -99 -99 1940 2017 normal 24 -99 72.0 -99 -99 -99 1979 2017 normal 36 -99 72.0 -99 -99 -99 1979 2017,2018 normal 48 -99 72.0 -99 -99 -99 1979 2018,2019,2020 normal 60 -99 72.0 -99 -99 -99 1979,1980 2020 normal