1991-2020 Degrees Fahrenheit 1 47.9 43.3 4.6 71 4 1960 2012 2009 2010 top-tenth 2 39.4 39.5 -0.1 47 28 1978 2012 2009 2009 normal 2009 3 37.1 37.5 -0.4 45 30 1978 2023 2009 2008 normal 1985,1989 4 36.7 37.6 -0.9 40 34 1978 2012 2009 2008 normal 5 39.3 39.5 -0.2 47 26 1978 2012 2009 2008 normal 6 41.9 42.4 -0.5 42 31 1978 2002,2012 2009 2008 normal 2019 7 45.5 46.2 -0.7 42 31 1977 2016 2009 2008 normal 1973 8 49.4 49.9 -0.5 44 29 1977 2016 2009 2008 normal 1997 9 52.0 53.0 -1.0 35 38 1977 2012 2009 2009 normal 2009 10 53.9 54.9 -1.0 38 35 1977 2012 2005 2009 normal 2004 11 54.8 55.7 -0.9 38 35 1977 2012 2009 2009 normal 2009 12 54.7 55.5 -0.8 38 35 1968 2012,2020 2004 2009 normal 1971 18 50.2 51.1 -0.9 34 35 1978 2017,2023 2004 2009 normal 24 54.8 55.5 -0.7 38 31 1978 2017 2005 2009 normal 1974 36 55.3 55.4 -0.1 48 17 1979 2022 2006 2009 top-third 48 55.4 55.4 0.0 48 13 1970,1980 2023 2007 2009 top-third 2001,2003,2007,2011 60 55.6 55.3 0.3 48 10 1970 2020,2023 2008 2009 top-third 2003,2008