1991-2020 Degrees Fahrenheit 1 45.3 42.9 2.4 71 5 1970 2002 2017 2012 top-tenth 2 40.3 39.1 1.2 66 10 1964 2017 2016 2017 top-third 3 36.6 34.2 2.4 72 4 1984 2017 2016 2017 top-tenth 4 33.5 30.0 3.5 74 2 1984 2015 2017 2015 top-tenth 5 32.0 27.6 4.4 73 1 1984 2018 2017 2018 highest 6 33.1 28.0 5.1 73 1 1973 2018 2017 2018 highest 7 34.8 30.3 4.5 73 1 1984 2018 2017 2018 highest 8 37.6 33.5 4.1 73 1 1984 2018 2017 2018 highest 9 40.4 36.8 3.6 73 1 1973,1992 2018 2017 2018 highest 10 43.0 39.7 3.3 73 1 1973 2018 2017 2018 highest 11 44.8 41.6 3.2 73 1 1984 2018 2017 2018 highest 12 45.3 42.5 2.8 73 1 1984 2018 2017 2018 highest 18 40.5 37.6 2.9 71 1 1993 2018 2017 2018 highest 24 45.0 42.5 2.5 71 1 1993 2018 2017 2018 highest 36 44.6 42.4 2.2 69 1 1975 2018 2013 2018 highest 48 -99 42.2 -99 -99 -99 1976 2019 normal 60 -99 42.1 -99 -99 -99 1977 2020 normal