1925-2000 Degrees Fahrenheit 1 9.4 3.7 5.7 78 21 1942 2017 1933 1930 top-third 2011 2 11.0 7.7 3.3 73 26 1956 2002 1933 1928 top-third 3 17.0 13.6 3.4 77 22 1956 2002 1933 1925 top-third 1925,2003 4 23.2 20.4 2.8 75 24 1956 2002 1933 1929 top-third 2004 5 28.4 26.2 2.2 74 25 1956 2002 1933 1929 top-third 1929,1969,2005 6 32.0 30.6 1.4 66 33 1956 2002 1933 1929 top-third 1947,1949,1989 7 34.4 33.3 1.1 63 36 1956 2017,2019 1933 1929 normal 1995,2006 8 34.6 33.8 0.8 54 45 1956 2019 1933 1929 normal 9 33.7 32.7 1.0 63 36 1955,1956 2019 1933 1926 normal 1937,1976,1991 10 31.5 30.5 1.0 63 36 1956 2019 1933 1926 normal 1991 11 29.9 28.1 1.8 75 24 1956 2019 1933 1926 top-third 1957,1969 12 26.4 26.0 0.4 43 56 1956 2019 1933 1931 normal 1936,2006 18 26.8 27.5 -0.7 21 77 1956 2019 1933 1931 bottom-third 1947 24 24.7 26.0 -1.3 14 84 1956 2019 1933 1932 bottom-third 36 24.4 26.0 -1.6 8 89 1956 2016 1934 1933 bottom-tenth 48 25.0 25.9 -0.9 16 80 1974 2019 1933 1932 bottom-third 1951,1971 60 25.1 25.9 -0.8 16 79 1975 2019 1934 1933 bottom-third 1935,1936,1950,1952,1967