1991-2020 Degrees Fahrenheit 1 40.2 45.3 -5.1 6 76 2018 2010 1950 1971 bottom-tenth 2 32.4 38.8 -6.4 6 76 1950 2012 1965 1971 bottom-tenth 3 26.0 32.7 -6.7 5 77 2014 2012 1965 1971 bottom-tenth 4 21.4 28.8 -7.4 2 79 2014 2012 1972 1971 bottom-tenth 5 21.5 27.6 -6.1 8 73 2014 2012 1965 1971 bottom-tenth 6 23.7 28.8 -5.1 9 70 2014 2012 1965 1971 bottom-third 7 28.2 31.6 -3.4 12 67 2014 2012 1970 1971 bottom-third 1962,1982 8 32.4 35.4 -3.0 17 62 2014 2016 1971 1971 bottom-third 1971 9 36.1 39.2 -3.1 15 64 2014 2012,2016 1965 1971 bottom-third 10 39.3 42.4 -3.1 8 71 1951 2012 1965 1971 bottom-tenth 1977,1994,1996 11 42.1 44.7 -2.6 14 65 1943,1951 2012 1970 1971 bottom-third 1977 12 43.1 45.8 -2.7 9 70 1943 2012 1970 1971 bottom-third 1963,1970 18 36.9 40.1 -3.2 4 72 1952 2017 1963 1971 bottom-tenth 1963 24 43.5 45.8 -2.3 8 68 1952 2017 1971 1971 bottom-tenth 1966,1970,1971,1978 36 43.3 45.8 -2.5 3 71 1953,1979 2000 1953 1971 bottom-tenth 48 43.5 45.8 -2.3 2 70 1980 2002 1972 1971 bottom-tenth 60 43.5 45.8 -2.3 1 69 1972 2002 1972 1971 lowest