1991-2020 Degrees Fahrenheit 1 66.6 60.3 6.3 68 1 1956 2015 2014 2015 highest 2 62.5 58.6 3.9 66 1 1955 2015 2014 2015 highest 3 60.9 57.5 3.4 62 1 1966 2015 2014 2015 highest 4 62.0 59.1 2.9 61 2 1973 1996 2014 1996 top-tenth 2018 5 65.6 62.7 2.9 61 1 1973 2015 2014 2015 highest 6 69.7 67.0 2.7 61 1 1973 1996,2015 2014 1996 highest 1996 7 72.8 70.9 1.9 60 2 1973 1996 2014 1996 top-tenth 8 75.6 73.8 1.8 60 2 1973 1996 2014 1996 top-tenth 9 77.3 75.4 1.9 61 1 1973 2015 2014 2015 highest 10 77.7 75.9 1.8 61 1 1972 2015 2014 2015 highest 11 77.3 75.6 1.7 61 1 1972 2015,2018 2014 2015 highest 2018 12 76.6 74.8 1.8 60 2 1972 2018 2014 2015 top-tenth 18 73.6 72.3 1.3 54 3 1974 2016,2018 2014 2015 top-tenth 24 76.2 74.9 1.3 55 2 1973,1977 2018 2014 2015 top-tenth 2016 36 75.8 74.9 0.9 47 5 1974 2018 2014 2015 top-tenth 48 75.6 74.9 0.7 42 5 1974 2018 2014 2015 top-tenth 60 75.1 74.8 0.3 34 8 1976 2018 2007 2015 top-third 2023