1991-2020 Degrees Fahrenheit 1 20.5 24.2 -3.7 41 52 1955 2012 1970 1968 normal 2 14.7 17.2 -2.5 46 47 1913 2012 1970 1968 normal 3 7.2 13.3 -6.1 28 65 1912 2012 1970 1969 bottom-third 4 6.1 12.8 -6.7 16 74 2014 2012 1965 1970 bottom-third 1957 5 9.5 15.6 -6.1 15 73 1979 2012 1967 1970 bottom-third 6 15.1 20.0 -4.9 16 71 1920 2012 1967 1970 bottom-third 1952,1989 7 20.8 25.0 -4.2 20 65 1920 2012 1970 1970 bottom-third 1970 8 26.2 29.7 -3.5 22 62 1920 2012 1967 1970 bottom-third 9 31.0 33.7 -2.7 27 57 1951 2012 1970 1969 bottom-third 1916,1960,1980 10 34.3 36.4 -2.1 30 52 1951 2012 1970 1969 normal 1969,1982 11 35.4 37.8 -2.4 23 59 1951 2012 1970 1969 bottom-third 1993 12 35.5 37.9 -2.4 23 59 1951 2012 1970 1969 bottom-third 1968 18 28.7 31.8 -3.1 14 64 1951 1999 1968 1970 bottom-third 1912,2015 24 35.3 37.8 -2.5 14 63 1952 2017 1968 1970 bottom-third 1956,2015 36 35.4 37.8 -2.4 12 60 1952 2000 1970 1970 bottom-third 1970,1979 48 35.4 37.8 -2.4 10 57 1952 2002 1970 1964 bottom-third 1957 60 35.2 37.7 -2.5 6 57 1953 2002 1970 1964 bottom-tenth 1972