1991-2020 Degrees Fahrenheit 1 40.5 41.6 -1.1 31 62 1917 1963 1981 1985 bottom-third 2 46.0 48.1 -2.1 27 64 1917 1963 1980 1985 bottom-third 3 50.8 53.2 -2.4 14 76 1951 2021 1979 1985 bottom-third 4 54.5 56.2 -1.7 18 72 1992 2021 1985 1984 bottom-third 2009 5 55.5 57.2 -1.7 14 73 1992 2021 1985 1984 bottom-third 6 55.5 56.3 -0.8 26 60 1950 2021 1985 1984 bottom-third 1962,1966 7 53.6 53.8 -0.2 46 40 1950 2021 1985 1984 normal 1915,1975 8 50.2 50.0 0.2 55 29 1950 2021 1985 1983 normal 9 45.6 45.6 0.0 55 29 1950 1998 1985 1984 normal 10 41.7 41.6 0.1 60 24 1950 1998 1985 1984 top-third 2015 11 37.9 38.8 -0.9 44 39 1950 1998 1985 1983 normal 1992 12 35.9 37.8 -1.9 31 51 1950 1998 1985 1984 normal 1989 18 42.0 44.0 -2.0 17 62 1951 2012 1979 1985 bottom-third 1969,1970 24 35.7 37.8 -2.1 20 56 1951 1999 1980 1985 bottom-third 36 36.0 37.8 -1.8 23 48 1951,1952 2000 1981 1985 bottom-third 1954,1962,1997 48 36.8 37.7 -0.9 37 29 1952 2001 1985 1984 normal 1976,1995 60 36.5 37.7 -1.2 29 33 1953,1954 2002 1983 1985 normal 1993