1991-2020 Degrees Fahrenheit 1 51.1 45.5 5.6 74 3 1960 2012 2015 2012 top-tenth 2 46.0 40.2 5.8 74 3 1960 2012 2015 2012 top-tenth 3 41.0 36.8 4.2 73 4 1979 2012 2015 2012 top-tenth 4 40.7 36.0 4.7 74 3 1979 2012 2015 2012 top-tenth 5 42.3 37.6 4.7 75 2 1979 2012 2015 2012 top-tenth 6 45.0 40.8 4.2 74 3 1979 2012 2015 2012 top-tenth 7 49.1 44.9 4.2 76 1 1979 2016 2015 2016 highest 8 52.3 49.0 3.3 74 3 1979 2012 2015 2012 top-tenth 9 55.3 52.4 2.9 73 3 1979 2012 2015 2012 top-tenth 10 57.5 54.7 2.8 73 3 1962 2012 2015 2012 top-tenth 11 58.1 55.7 2.4 73 3 1962 2012 2015 2012 top-tenth 12 58.0 55.7 2.3 73 3 1962 2012 2015 2012 top-tenth 18 52.0 50.7 1.3 68 8 1979 2017 2015 2013 top-tenth 24 56.7 55.6 1.1 68 7 1952,1979 2013,2017 2015 2013 top-tenth 36 55.7 55.6 0.1 55 19 1979 2013 2015 2014 top-third 2003,2009 48 56.2 55.6 0.6 64 9 1980 2018,2019 2012 2015 top-third 2007 60 56.8 55.6 1.2 71 1 1962 2016,2020 2015 2016 highest 2020