1991-2020 Degrees Fahrenheit 1 64.9 63.6 1.2 45 22 1976 1965 2009 2007 top-third 1971 2 70.2 69.2 1.0 49 18 1976 2016 2009 2007 top-third 3 75.0 74.0 1.0 52 15 1976 2021 2009 2006 top-third 1981 4 79.0 77.9 1.1 54 13 1976 2015 2009 2006 top-third 5 80.4 80.3 0.1 42 25 1976 1951 2008 2009 normal 1965,1994 6 81.6 81.5 0.1 41 26 1976 1951,2011 2008 2009 normal 1952 7 81.5 81.6 -0.1 38 29 1976 1998 2008 2009 normal 1985 8 80.4 80.7 -0.3 34 32 1976 2011 2008 2009 normal 1965,1982,1983 9 78.6 79.3 -0.7 24 42 1976 2011 2007 2009 normal 2014 10 76.2 77.4 -1.2 16 49 1976 2011 2007 2009 bottom-third 1981,2004 11 74.0 75.4 -1.4 12 53 1970 2011 2007 2009 bottom-third 12 72.1 73.8 -1.7 11 54 1970,1976 2000,2011 2007 2009 bottom-third 18 75.6 76.3 -0.7 24 41 1976 2012 2008 2009 normal 1967,1984,1991,2008 24 73.5 73.8 -0.3 40 23 1976 2012 2008 2009 normal 1981,1986,2002,2007 36 73.5 73.8 -0.3 37 24 1970 2000 2009 2008 normal 2008 48 73.1 73.7 -0.6 24 35 1970,1971 2001 1993 2009 normal 1986,1991,1992 60 73.5 73.7 -0.2 34 23 1970 1956,2002,2020 2008 2009 normal 1996