1991-2020 Degrees Fahrenheit 1 72.7 71.9 0.8 98 30 1924 2012 1909 1901 top-third 2 68.7 69.7 -1.0 64 64 1929 2012 1909 1901 normal 3 62.9 65.8 -2.9 24 103 1917 2012 1907 1909 bottom-third 1938,1948,1950 4 59.4 61.0 -1.6 48 78 1917 1991 1909 1908 normal 1933,1984,2003 5 55.8 56.0 -0.2 91 33 1917,1924,1926 2012 1909 1901 top-third 1901 6 50.2 51.3 -1.1 77 47 1917 2012 1909 1903 normal 1970,1993,2009 7 -99 47.8 -99 -99 -99 1917 2012 normal 8 -99 45.8 -99 -99 -99 1904 2012 normal 9 -99 45.2 -99 -99 -99 1904 2012 normal 10 -99 45.9 -99 -99 -99 1904 2012 normal 11 -99 47.5 -99 -99 -99 1918 2012 normal 12 -99 49.4 -99 -99 -99 1904 2012 normal 18 -99 50.0 -99 -99 -99 1918 2012 normal 24 -99 49.4 -99 -99 -99 1918 2017 normal 36 -99 49.4 -99 -99 -99 1918 2012 normal 48 -99 49.4 -99 -99 -99 1918 2013 normal 60 -99 49.4 -99 -99 -99 1920,1927 2002 normal