1991-2020 Degrees Fahrenheit 1 31.4 24.2 7.2 88 5 1955 2012 1972 1973 top-tenth 2 19.6 17.2 2.4 78 15 1913 2012 1972 1961 top-third 2004 3 15.8 13.3 2.5 80 13 1912 2012 1972 1973 top-third 1990 4 12.5 12.8 -0.3 67 23 2014 2012 1972 1958 top-third 1926 5 14.8 15.6 -0.8 62 26 1979 2012 1972 1958 top-third 1953 6 18.8 20.0 -1.2 54 33 1920 2012 1972 1964 normal 7 23.2 25.0 -1.8 49 36 1920 2012 1972 1964 normal 8 28.4 29.7 -1.3 51 33 1920 2012 1972 1964 normal 9 32.2 33.7 -1.5 43 41 1951 2012 1972 1964 normal 1953 10 35.1 36.4 -1.3 41 41 1951 2012 1972 1964 normal 11 37.2 37.8 -0.6 56 26 1951 2012 1972 1964 top-third 1976,1988,2001,2013 12 37.1 37.9 -0.8 51 31 1951 2012 1972 1964 normal 1958 18 29.4 31.8 -2.4 24 54 1951 1999 1972 1969 bottom-third 1955 24 35.8 37.8 -2.0 27 50 1952 2017 1972 1964 normal 36 35.7 37.8 -2.1 17 55 1952 2000 1972 1964 bottom-third 48 35.5 37.8 -2.3 12 55 1952 2002 1972 1964 bottom-third 1958,1962 60 35.6 37.7 -2.1 11 52 1953 2002 1972 1964 bottom-third 1980