1991-2020 Degrees Fahrenheit 1 52.0 47.8 4.2 93 15 1917 1963 2009 2007 top-third 2016 2 55.5 54.4 1.1 78 29 1917 1931 2009 2008 top-third 2008 3 61.1 58.9 2.2 94 12 1917 1947 2009 2007 top-third 1953,2015 4 63.8 61.8 2.0 92 14 1992 1947 2009 2007 top-third 5 64.4 62.9 1.5 86 20 1992 1931 2009 2007 top-third 1941 6 63.4 62.0 1.4 89 17 1917 1931 2009 2007 top-third 1963,1988 7 61.8 59.6 2.2 99 7 1917 1955 2009 2007 top-tenth 2007,2016 8 58.8 56.0 2.8 102 4 1917 2012 2009 2010 top-tenth 9 54.0 51.9 2.1 99 7 1917 2012 2009 1998 top-tenth 10 49.6 48.1 1.5 91 14 1917 2012 2009 2006 top-third 11 46.6 45.6 1.0 88 17 1917 2012 2009 2007 top-third 1938,2002 12 46.2 44.6 1.6 92 13 1917 2012 2009 2007 top-third 1919 18 50.6 50.4 0.2 70 33 1917 2012 2009 2007 top-third 1933,1991,2011 24 44.3 44.6 -0.3 63 39 1918 2017 2009 2008 normal 1920,1987,1992,2002 36 44.0 44.6 -0.6 54 46 1952 2012 1998 2009 normal 1936,1944,1946,1947,1983 48 44.6 44.6 0.0 74 24 1918 1934,2013 2009 2009 top-third 1955,2009,2021 60 44.9 44.6 0.3 80 16 1969,1997 1934 2009 2009 top-third 1942,2004,2009,2017,2018