1991-2020 Degrees Fahrenheit 1 23.1 25.3 -2.2 50 72 1918 2006 1925 1926 normal 2 23.6 28.0 -4.4 32 88 1918 1932 1926 1924 bottom-third 1903 3 27.7 32.4 -4.7 21 98 1977 2002 1926 1924 bottom-third 1915,1978 4 33.5 37.6 -4.1 15 103 1977 1932 1926 1925 bottom-third 1910 5 39.5 43.0 -3.5 17 101 1977 1932 1926 1924 bottom-third 1920,1970,1984 6 45.0 47.8 -2.8 20 98 1977 1932 1926 1924 bottom-third 2009 7 49.0 51.5 -2.5 23 95 1977 1932 1926 1924 bottom-third 2009 8 50.8 53.8 -3.0 13 105 1918 1932 1926 1926 bottom-third 1926 9 51.9 54.5 -2.6 14 104 1918 1932 1926 1924 bottom-third 1938,1963,1968,1997 10 50.8 54.0 -3.2 9 108 1918 1932 1925 1926 bottom-tenth 11 48.8 52.5 -3.7 5 112 1918 2013 1925 1926 bottom-tenth 12 47.1 50.5 -3.4 9 107 1918 2013 1925 1926 bottom-tenth 18 46.0 49.6 -3.6 3 107 1918 2017 1918 1926 bottom-tenth 24 47.8 50.5 -2.7 8 100 1918 2013 1926 1921 bottom-tenth 1908 36 47.4 50.5 -3.1 2 99 1918 2013 1919 1926 bottom-tenth 1919 48 47.6 50.5 -2.9 2 94 1918 2019,2020 1918 1921 bottom-tenth 60 -99 50.4 -99 -99 -99 1918 2020,2021 normal