1991-2020 Degrees Fahrenheit 1 35.8 34.8 1.0 54 24 1979 2017 1969 1957 top-third 2 29.6 32.5 -2.9 35 43 1979 1992 1969 1967 normal 1947,2007 3 29.7 32.8 -3.1 22 56 1979 1992 1969 1968 bottom-third 4 32.9 35.6 -2.7 28 50 1979 2000 1969 1968 normal 1968 5 36.8 39.9 -3.1 14 64 1979 2017 1962 1969 bottom-third 1985,1994 6 42.2 44.8 -2.6 20 58 1979 2017 1969 1967 bottom-third 1975,1986,1996 7 47.0 49.5 -2.5 19 59 1979 2017 1969 1967 bottom-third 8 51.0 53.3 -2.3 20 57 1979 2017 1969 1967 bottom-third 1952,1959,1971 9 53.0 55.7 -2.7 16 61 1979 2017 1969 1967 bottom-third 1975,1986 10 54.2 56.7 -2.5 16 61 1977 2017 1969 1967 bottom-third 1997 11 54.3 56.6 -2.3 18 59 1962 2017 1969 1967 bottom-third 1959 12 52.8 55.7 -2.9 9 68 1962 2013 1969 1969 bottom-third 1959,1969,1997 18 49.1 52.0 -2.9 7 70 1979 2017 1969 1969 bottom-tenth 1961,1969 24 52.8 55.6 -2.8 8 68 1962,1963 2013 1969 1968 bottom-tenth 1978 36 52.8 55.6 -2.8 5 70 1979 2013 1963 1969 bottom-tenth 48 53.0 55.6 -2.6 6 68 1962,1980 2019 1963 1969 bottom-tenth 1952,1961 60 53.2 55.6 -2.4 8 65 1963 2017,2020 1963 1969 bottom-third 1972