1991-2020 Degrees Fahrenheit 1 34.0 30.6 3.4 58 17 1951 2012 1976 1973 top-third 2 30.3 25.3 5.0 66 9 2019 1999 1976 1977 top-third 3 21.3 22.4 -1.1 37 38 1950 1992 1975 1976 normal 4 20.4 21.9 -1.5 37 37 1950 1992 1975 1976 normal 5 21.6 23.6 -2.0 33 41 1979 2000 1974 1976 normal 1986 6 25.0 27.1 -2.1 29 45 1952 2000 1972 1976 normal 7 30.1 31.6 -1.5 33 41 1952 2012 1974 1976 normal 1974 8 35.2 36.3 -1.1 37 37 1952 1999 1975 1976 normal 9 39.0 40.0 -1.0 35 39 1952 1999 1975 1976 normal 1974 10 41.5 42.3 -0.8 35 38 1952 2016 1975 1976 normal 11 42.8 43.3 -0.5 38 35 1952 1992,1999 1975 1976 normal 12 43.1 43.2 -0.1 44 29 1952 1999 1976 1964 normal 2015 18 38.2 37.9 0.3 52 20 1952 2000 1976 1964 top-third 1982 24 42.9 43.2 -0.3 42 29 1952 2000 1976 1964 normal 2012 36 42.6 43.2 -0.6 39 30 1952 2000 1976 1964 normal 1963,1964 48 42.5 43.3 -0.8 38 29 1953 1992,2001 1976 1964 normal 1982,1998,2013 60 42.4 43.3 -0.9 33 32 1954 1992 1976 1964 normal