1991-2020 Degrees Fahrenheit 1 72.1 70.7 1.4 46 14 1992 1995 2019 2018 top-third 2 73.9 71.6 2.3 54 6 1992 2010 2019 2012 top-tenth 3 72.4 70.6 1.8 51 9 1992 2012 2019 2018 top-third 2011,2018 4 68.5 67.7 0.8 45 15 1992 2012 2019 2018 top-third 5 63.6 63.6 0.0 38 22 1992 2010 2019 2018 normal 1964 6 59.5 58.9 0.6 46 14 1965,1992 2012 2019 2016 top-third 2000,2011 7 54.9 54.2 0.7 44 16 1978 2012 2019 2018 top-third 8 52.0 50.5 1.5 51 9 1978 2012 2019 2017 top-third 9 49.9 48.2 1.7 53 7 1978 2012 2019 2016 top-third 10 48.3 47.4 0.9 45 14 1996,2014 2012 2019 2017 top-third 1983 11 48.5 47.7 0.8 43 16 1979 2012 2019 2017 top-third 12 49.9 49.0 0.9 46 13 1994 2012 2019 2017 top-third 1995 18 52.7 52.3 0.4 41 18 1979 2012 2019 2018 top-third 2018 24 49.1 49.0 0.1 42 16 1979 2017 2019 2018 top-third 1992,2001,2010 36 49.2 48.9 0.3 41 16 1979 2012 2016 2019 top-third 48 49.6 48.9 0.7 49 7 1980 2013 2017 2019 top-third 2008 60 50.1 48.9 1.2 54 1 1982 2020 2019 2020 highest