1991-2020 Degrees Fahrenheit 1 66.7 70.7 -4.0 16 98 1928 1956 1916 1918 bottom-third 2 61.4 65.1 -3.7 13 100 1915 1934 1917 1918 bottom-third 3 54.7 59.8 -5.1 4 108 1995 2012 1917 1918 bottom-tenth 1983 4 50.6 55.3 -4.7 4 108 1915 2012 1917 1918 bottom-tenth 1958,1983,1995 5 46.7 50.7 -4.0 6 105 1917 2012 1917 1918 bottom-tenth 6 44.0 47.3 -3.3 13 97 1915 2012 1917 1918 bottom-third 1942,1951,1957 7 41.2 44.9 -3.7 7 102 1915 2012 1917 1918 bottom-tenth 1978 8 40.0 44.2 -4.2 5 104 1917 2012 1917 1918 bottom-tenth 9 40.6 45.1 -4.5 3 106 1917 2012 1917 1918 bottom-tenth 10 -99 47.1 -99 -99 -99 1917 1934 normal 11 -99 49.5 -99 -99 -99 1993 2012 normal 12 -99 51.7 -99 -99 -99 1993 2012 normal 18 -99 50.2 -99 -99 -99 1924 2016 normal 24 -99 51.7 -99 -99 -99 1917 2017 normal 36 -99 51.7 -99 -99 -99 1917 2017,2018 normal 48 -99 51.7 -99 -99 -99 1918 2018 normal 60 -99 51.7 -99 -99 -99 1930,1931 2006 normal