1991-2020 Degrees Fahrenheit 1 85.0 88.7 -3.7 9 59 1965 2021 1969 1970 bottom-third 2 79.3 84.3 -5.0 3 65 1965 2001,2006 1965 1970 bottom-tenth 3 75.5 80.3 -4.8 4 64 1967,1975 2000 1967 1970 bottom-tenth 4 73.0 76.8 -3.8 8 60 1975 2004 1967 1970 bottom-third 5 70.2 73.5 -3.3 7 61 1975 2014,2015,2016,2017 1967 1970 bottom-tenth 1977 6 67.5 70.8 -3.3 7 59 1975 2014 1967 1970 bottom-tenth 7 65.5 68.7 -3.2 6 56 1975 2015 1967 1970 bottom-tenth 8 65.2 68.1 -2.9 5 57 1975 1996 1965 1970 bottom-tenth 9 66.0 69.1 -3.1 3 58 1975 1996,2015 1971 1970 bottom-tenth 10 67.9 71.0 -3.1 4 57 1973 1996 1971 1970 bottom-tenth 11 70.3 73.1 -2.8 6 55 1973 1996 1965 1970 bottom-tenth 1983 12 72.3 74.9 -2.6 8 53 1975 1996 1969 1970 bottom-third 18 71.0 73.5 -2.5 9 51 1976 2015 1956 1970 bottom-third 24 72.8 74.9 -2.1 9 47 1973,1975,1976 2018 1970 1970 bottom-third 1963,1967,1970 36 72.6 74.9 -2.3 6 45 1975,1977 2017,2018 1967 1970 bottom-third 1967 48 73.0 74.9 -1.9 9 37 1975,1976 2018 1970 1970 bottom-third 1969,1970 60 72.9 74.8 -1.9 8 33 1977 2018 1969 1970 bottom-third 1972