1991-2020 Degrees Fahrenheit 1 7.2 18.9 -11.7 3 69 1977 2006 1963 1962 bottom-tenth 2 14.3 21.6 -7.3 8 64 1977 2002 1963 1962 bottom-third 3 21.9 26.6 -4.7 11 61 1977 2002 1952 1962 bottom-third 1952 4 29.7 32.4 -2.7 14 58 1977 2002 1952 1962 bottom-third 5 35.5 38.4 -2.9 13 59 1977 2016 1952 1962 bottom-third 6 41.3 43.7 -2.4 11 60 1977 2002 1952 1962 bottom-third 1993 7 45.2 47.7 -2.5 9 62 1977 2002 1952 1962 bottom-third 1994 8 48.0 50.3 -2.3 11 60 1977 2002,2017 1952 1962 bottom-third 9 49.7 51.2 -1.5 14 57 1977 2002 1962 1962 bottom-third 1962,1968,1969,2001 10 49.3 50.8 -1.5 14 57 1977 2002 1962 1961 bottom-third 11 47.5 49.4 -1.9 10 61 1977 2013 1952 1962 bottom-third 12 45.1 47.2 -2.1 9 62 1979 2013 1959 1962 bottom-third 1959 18 44.2 46.0 -1.8 7 62 1979 2017 1963 1962 bottom-tenth 1970,2014 24 45.6 47.2 -1.6 9 60 2015 2013 1963 1962 bottom-third 36 45.5 47.2 -1.7 2 65 1979 2013,2018 1963 1962 bottom-tenth 1980 48 45.8 47.2 -1.4 4 61 1980 2002 1962 1962 bottom-tenth 1962 60 45.6 47.2 -1.6 2 61 1980 2003 1963 1962 bottom-tenth 1979