1991-2020 Degrees Fahrenheit 1 61.4 61.3 0.1 51 39 1969 1995 1979 1977 normal 2 59.6 56.4 3.2 82 7 1969 1988 1979 1977 top-tenth 1922 3 54.2 50.5 3.7 83 6 1950 1991 1979 1977 top-tenth 4 44.6 43.9 0.7 66 21 1950 1977,2012 1979 1977 top-third 2015 5 37.1 37.2 -0.1 60 27 1950 1987 1979 1977 top-third 2001 6 31.2 31.9 -0.7 53 34 1950 2012 1979 1977 normal 7 28.9 29.0 -0.1 65 21 1950 2012 1979 1921 top-third 8 28.1 28.7 -0.6 59 26 1979 2012 1979 1976 top-third 1915 9 29.1 30.1 -1.0 51 33 1920 2012 1979 1976 normal 1922,1975 10 31.5 32.6 -1.1 53 30 1950 2012 1979 1976 normal 1961,1992,2011 11 34.1 35.4 -1.3 46 37 1920 2012 1979 1977 normal 1977,1990 12 36.8 37.9 -1.1 46 37 1920,1950 2012 1979 1976 normal 18 32.9 35.9 -3.0 15 65 1951 1999 1979 1978 bottom-third 1949,1960 24 35.0 37.8 -2.8 11 67 1951 1999 1979 1978 bottom-third 36 34.9 37.8 -2.9 5 68 1952 2000 1979 1979 bottom-tenth 1979 48 35.4 37.7 -2.3 8 60 1952 2001 1972 1979 bottom-third 1957,1972 60 35.8 37.7 -1.9 18 45 1953 2002 1979 1979 bottom-third 1979,1981,1997