1991-2020 Degrees Fahrenheit 1 71.8 80.0 -8.2 1 68 1977 1997 1977 1976 lowest 2 71.4 76.1 -4.7 5 63 1975 2000 1975 1976 bottom-tenth 3 67.4 72.9 -5.5 2 66 1975 2004 1975 1976 bottom-tenth 4 65.7 69.7 -4.0 5 63 1975 2014 1975 1976 bottom-tenth 5 63.4 67.2 -3.8 4 62 1975 2014 1975 1976 bottom-tenth 6 61.8 65.3 -3.5 3 59 1975 2014,2015 1975 1976 bottom-tenth 7 61.9 65.1 -3.2 3 59 1975 1996 1975 1976 bottom-tenth 8 63.4 66.6 -3.2 3 58 1973 1996 1975 1976 bottom-tenth 9 65.5 69.1 -3.6 3 58 1973 1996 1975 1976 bottom-tenth 10 67.9 71.6 -3.7 3 58 1973 1996 1975 1976 bottom-tenth 11 69.9 73.6 -3.7 2 59 1973 1996 1975 1976 bottom-tenth 1975 12 71.3 74.9 -3.6 2 59 1973 1996 1973 1976 bottom-tenth 18 68.6 71.7 -3.1 2 55 1976 2015 1976 1975 bottom-tenth 24 71.9 74.9 -3.0 3 53 1973,1974 2018 1974 1976 bottom-tenth 36 71.8 74.9 -3.1 2 49 1975 2017,2018 1975 1976 bottom-tenth 48 72.0 74.9 -2.9 3 43 1975,1976 2018 1976 1974 bottom-tenth 60 71.8 74.8 -3.0 1 40 1977 2018 1977 1976 lowest