1991-2020 Degrees Fahrenheit 1 61.8 60.9 0.9 54 21 1983 2012 2019 2018 top-third 2 58.9 56.5 2.4 72 3 1983 2012 2019 2018 top-tenth 3 54.3 52.0 2.3 72 3 1983 2012 2019 2018 top-tenth 4 50.4 47.8 2.6 73 2 1983 2012 2019 2012 top-tenth 5 46.1 43.2 2.9 74 1 1984 2020 2019 2020 highest 6 41.1 38.8 2.3 69 6 1984 2018 2019 2018 top-tenth 7 37.7 35.9 1.8 66 7 1979,1984 2018 2019 2018 top-tenth 8 36.8 35.2 1.6 64 9 1973 2018 2019 2018 top-third 9 37.1 36.2 0.9 58 15 1973,1984 2018 2019 2018 top-third 2003 10 39.3 38.2 1.1 63 10 1973,1992 2018 2019 2018 top-third 1978 11 41.6 40.5 1.1 63 10 1973 2018 2019 2018 top-third 12 43.6 42.5 1.1 63 10 1973 2018 2019 2018 top-third 18 41.3 41.3 0.0 53 20 1965,1993 2018 2013 2019 top-third 24 42.8 42.5 0.3 56 15 1993 2018 2013 2019 top-third 1996,2002 36 43.8 42.5 1.3 66 3 1975 2018 2013 2019 top-tenth 48 44.0 42.3 1.7 65 2 1976 2019 2013 2019 top-tenth 60 44.0 42.2 1.8 64 1 1977 2020 2013 2020 highest