1991-2020 Degrees Fahrenheit 1 27.7 28.9 -1.2 53 45 1934 2017 2010 2009 normal 2 25.5 28.6 -3.1 29 69 2015 2017 2004 2010 bottom-third 3 26.4 30.4 -4.0 21 76 1936 1932 2003 2010 bottom-third 1981 4 30.7 33.7 -3.0 28 69 1977 2002 2003 2010 bottom-third 5 35.3 37.8 -2.5 31 66 1977 2017 2003 2010 bottom-third 6 40.2 42.3 -2.1 31 66 1977 2017 2003 2010 bottom-third 1948 7 45.0 46.5 -1.5 41 56 1977 2017 2003 2010 normal 1957,1987,1993 8 48.7 49.7 -1.0 56 41 1977 2017 2010 2009 normal 1986 9 51.0 51.8 -0.8 63 34 1977 2017 2010 2009 normal 1939,1947,2007 10 51.9 52.5 -0.6 68 29 1977 2017 2010 2008 top-third 1949 11 52.0 52.0 0.0 76 21 1977 2017 2010 2008 top-third 12 50.8 50.7 0.1 77 20 1927 2017 2010 2008 top-third 1950,1960 18 47.5 47.8 -0.3 67 28 1941,1979 2017 2010 2009 top-third 24 50.1 50.6 -0.5 64 31 1928 2017 2010 2009 top-third 1954 36 50.1 50.6 -0.5 69 24 1929 2018,2023 2005 2010 top-third 1988,1989,1991,2004 48 50.4 50.6 -0.2 71 20 1930 2023 2010 2009 top-third 1993 60 50.4 50.5 -0.1 68 21 1931 2020,2023 2007 2010 top-third 2006