1991-2020 Degrees Fahrenheit 1 60.9 57.8 3.1 71 11 1967 1977 2006 1998 top-third 2 53.1 51.5 1.6 65 17 1947 1977 2005 2006 top-third 3 47.4 45.0 2.4 69 13 1950 2012 2005 2006 top-third 4 38.8 38.9 -0.1 59 23 1950 2012 2003 2006 top-third 1992 5 35.3 34.4 0.9 64 17 2014 2012 2005 2006 top-third 1977 6 34.1 32.5 1.6 71 10 2014 2012 2005 2006 top-third 7 34.6 32.8 1.8 67 12 2014 2012 2005 2006 top-third 8 35.8 34.7 1.1 68 11 2014 2012 2005 2006 top-third 2021 9 38.3 37.7 0.6 65 14 1943 2016 2004 2006 top-third 10 41.4 40.9 0.5 67 12 1943 2012 2005 2006 top-third 1995,2005 11 44.5 43.6 0.9 67 12 1943 2012 2005 2006 top-third 12 46.4 45.6 0.8 67 12 1943 2012 2005 2006 top-third 18 42.7 41.2 1.5 70 8 1951 1999 2005 2006 top-tenth 24 47.4 45.6 1.8 71 5 1952,1979 2017 2006 2000 top-tenth 36 46.8 45.6 1.2 69 5 1979 2000 2006 2000 top-tenth 2013 48 46.5 45.6 0.9 67 5 1968 2001,2002 2006 2002 top-tenth 2018,2019 60 46.1 45.6 0.5 63 7 1969 2002 2005 2006 top-tenth 2004,2008,2010,2016