1991-2020 Degrees Fahrenheit 1 59.8 55.3 4.5 73 3 2011 1958 1986 1980 top-tenth 2 56.7 50.5 6.2 74 2 1975 1980 1986 1980 top-tenth 3 50.2 46.3 3.9 74 2 2002 2012 1986 1987 top-tenth 4 46.3 42.1 4.2 73 3 2019 2016 1986 1987 top-tenth 5 43.0 39.0 4.0 73 3 1979 1992 1986 1987 top-tenth 6 41.1 37.1 4.0 72 3 1979 1992 1986 1987 top-tenth 7 39.8 36.9 2.9 69 6 1979 1992 1986 1981 top-tenth 8 41.0 38.3 2.7 69 6 1979 2016 1986 1981 top-tenth 9 42.4 40.9 1.5 65 10 1979 2016 1986 1981 top-third 10 45.1 43.9 1.2 64 11 1979 2016 1986 1981 top-third 11 47.3 46.6 0.7 60 15 1979 2016 1986 1981 top-third 2008 12 49.1 48.1 1.0 62 13 1979 2016 1986 1981 top-third 18 45.5 44.4 1.1 62 12 1979 2016 1986 1981 top-third 1999 24 47.4 48.1 -0.7 35 39 1979 2016 1986 1984 normal 1963 36 46.7 48.1 -1.4 20 53 1952 2017 1986 1985 bottom-third 1995,1996,2020 48 46.9 48.2 -1.3 25 47 1952 2016 1986 1984 normal 1957,1958,1998 60 47.1 48.2 -1.1 27 44 1953,1973 2016 1986 1985 normal 1977,1989