1991-2020 Degrees Fahrenheit 1 56.8 56.1 0.7 65 20 1940 2017 1973 1960 top-third 2001 2 51.5 50.8 0.7 60 25 1940 2012 1972 1973 top-third 1994 3 46.2 46.4 -0.2 54 31 1940 2012 1973 1973 normal 1973 4 44.3 43.6 0.7 67 18 1940 2023 1973 1953 top-third 5 43.3 42.9 0.4 64 21 1940 2012 1973 1973 top-third 1954,1973 6 44.2 43.7 0.5 66 18 1940 2012 1973 1953 top-third 2007 7 46.3 45.8 0.5 65 19 1940 2012 1973 1949 top-third 8 49.4 48.9 0.5 69 15 1940 2012 1973 1974 top-third 9 52.7 52.0 0.7 70 14 1977 2017 1973 1974 top-third 10 55.1 54.7 0.4 69 15 1977 2017 1973 1974 top-third 1995,2013 11 56.9 56.5 0.4 67 16 1977 2012 1973 1974 top-third 2000,2013 12 57.3 57.3 0.0 63 20 1977 2012 1973 1954 top-third 1954,1998 18 52.7 52.7 0.0 59 23 1941 2017 1973 1954 top-third 24 56.5 57.2 -0.7 51 30 1978 2017 1973 1972 normal 1955,1972,1990,2005 36 56.5 57.2 -0.7 52 27 1979 2013 1973 1955 normal 1951,1976,1996,1997,1998,2003 48 56.5 57.2 -0.7 47 30 1964,1980 2023 1973 1974 normal 1995 60 56.2 57.1 -0.9 33 42 1965 2023 1973 1957 normal 1949,1950,1975,1987,1988