1991-2020 Degrees Fahrenheit 1 44.6 38.7 5.9 97 5 1960 2012 2009 1945 top-tenth 2 36.4 34.6 1.8 89 13 1934 2012 2009 2002 top-third 1945,1997 3 33.6 32.4 1.2 85 15 1978 2012,2020 2009 2006 top-third 1991 4 32.8 32.6 0.2 75 25 1978 2012 2009 2008 top-third 5 35.4 34.5 0.9 78 20 1934 2012 2009 2007 top-third 6 37.9 37.5 0.4 74 23 1934 2012 2009 2008 top-third 1949,2013 7 41.3 41.3 0.0 74 23 1934 2012 2009 2008 top-third 1953,1985 8 45.2 45.1 0.1 77 20 1963 2012 2009 2008 top-third 1949,1974 9 47.9 48.3 -0.4 72 25 1963 2012 2009 2008 top-third 10 49.7 50.3 -0.6 68 29 1963 2012 2009 2008 top-third 1976 11 50.6 51.2 -0.6 67 30 1941 2012 2009 2008 top-third 12 50.6 51.1 -0.5 73 24 1941 2012 2009 2008 top-third 1950,1974 18 45.6 46.5 -0.9 61 32 1941 2017 2004 2009 normal 2014 24 50.3 51.0 -0.7 65 28 1926,1941 2017,2021 2005 2009 top-third 1986 36 50.7 51.0 -0.3 67 22 1941,1979 2022 2005 2009 top-third 48 50.9 50.9 0.0 68 18 1980 2023 2006 2009 top-third 2001 60 51.2 50.9 0.3 70 13 1944 2023 2009 2009 top-third 2002,2008,2009