1991-2020 Degrees Fahrenheit 1 58.7 55.9 2.8 80 5 1940 2017 2010 2006 top-tenth 2 52.0 50.5 1.5 72 13 1940 2012 2009 2010 top-third 1976,2020 3 47.8 46.2 1.6 72 13 1940 2012 2010 2002 top-third 4 43.6 43.4 0.2 59 26 1940 2023 2010 2010 top-third 2010 5 41.6 42.6 -1.0 48 37 1940 2012 2004 2010 normal 1975 6 42.7 43.5 -0.8 49 35 1940 2012 2009 2010 normal 2009 7 44.9 45.6 -0.7 49 35 1940 2012 2009 2010 normal 8 48.3 48.6 -0.3 54 30 1940 2012 2010 2008 normal 9 51.7 51.8 -0.1 62 22 1977 2017 2010 2008 top-third 1954,1995 10 54.7 54.5 0.2 65 19 1977 2012,2017 2010 2008 top-third 1949 11 57.0 56.3 0.7 71 12 1977 2012 2010 2008 top-third 12 57.9 57.0 0.9 71 12 1977 2012 2010 2008 top-third 18 53.2 52.5 0.7 71 11 1941 2017 2010 2008 top-third 2007,2018 24 57.2 57.0 0.2 66 15 1978 2017 2010 2009 top-third 1999,2019 36 56.9 57.0 -0.1 62 17 1979 2013,2022,2023 2006 2010 top-third 2002,2006 48 57.3 56.9 0.4 65 12 1980 2023 2010 2009 top-third 60 57.2 56.9 0.3 62 13 1965,1968,1981 2023 2007 2010 top-third 2015,2017