1991-2020 Degrees Fahrenheit 1 62.3 57.7 4.6 88 5 1989 2021 2014 1984 top-tenth 2 64.5 60.9 3.6 90 3 1976 2021 2014 2015 top-tenth 3 68.3 65.2 3.1 85 3 1976 2021 2014 2015 top-tenth 4 71.5 69.4 2.1 85 3 1976 2021 2014 2015 top-tenth 5 74.4 72.7 1.7 85 3 1976 2021 2014 2007 top-tenth 2007 6 76.5 74.9 1.6 84 3 1976 2016 2014 2015 top-tenth 7 77.5 76.2 1.3 82 5 1976 2021 2014 2011 top-tenth 8 77.7 76.4 1.3 82 5 1976 2021 2014 2011 top-tenth 9 77.2 75.9 1.3 82 4 1976 2016 2014 2011 top-tenth 1998 10 76.0 74.9 1.1 80 6 1976 2016 2014 2012 top-tenth 2012 11 74.0 73.5 0.5 76 9 1976 2016 2014 2012 top-third 2018 12 72.2 72.0 0.2 71 13 1940 2017 2014 2012 top-third 2008 18 72.9 72.9 0.0 66 16 1940 2017 2014 2012 top-third 2007 24 71.3 72.0 -0.7 55 24 1979 2017 2014 2013 top-third 1954,2003,2010 36 71.3 72.0 -0.7 50 25 1980 2017 2003 2014 top-third 48 71.8 72.0 -0.2 51 20 1979 2019 2010 2014 top-third 2005 60 72.1 72.0 0.1 56 12 1979 2020 2014 2013 top-third 2007,2013