1991-2020 Degrees Fahrenheit 1 54.5 51.2 3.3 81 13 1924 1977 1985 1986 top-third 2 50.5 44.7 5.8 92 2 1909 1977 1986 1977 top-tenth 3 43.2 37.7 5.5 88 4 1950 2010 1986 1977 top-tenth 4 37.9 30.8 7.1 90 2 1917 1998 1986 1987 top-tenth 5 32.3 25.6 6.7 89 3 1950 1998 1986 1987 top-tenth 6 29.3 23.2 6.1 87 3 1950,1979 1998 1986 1987 top-tenth 7 27.8 23.7 4.1 83 5 1979 2012 1986 1987 top-tenth 8 29.3 25.9 3.4 81 6 1920 2012 1986 1987 top-tenth 2017 9 31.8 29.1 2.7 77 8 1920 2012 1986 1987 top-tenth 10 34.6 32.5 2.1 75 9 1920 2012 1986 1987 top-third 11 37.4 35.4 2.0 76 8 1920 2012 1986 1987 top-tenth 2002,2021 12 39.2 37.5 1.7 72 10 1979 2012 1986 1987 top-third 18 33.7 32.7 1.0 64 15 1951 1999 1986 1987 top-third 24 37.0 37.5 -0.5 55 22 1951 1999,2017 1986 1984 top-third 1991,2005,2020 36 36.8 37.4 -0.6 50 22 1952 2000 1986 1985 top-third 2011,2020 48 36.9 37.4 -0.5 46 21 1952,1953 2001 1986 1987 top-third 1988 60 37.0 37.3 -0.3 43 20 1970 2002 1986 1987 top-third 2011