1991-2020 Degrees Fahrenheit 1 27.6 30.5 -2.9 28 50 1979 2006 2011 2013 normal 2 28.4 32.2 -3.8 19 59 1984 1992 2011 2013 bottom-third 3 33.0 36.3 -3.3 16 62 1977 2002 2001 2013 bottom-third 1951 4 38.8 41.6 -2.8 13 65 1977 2002 2010 2013 bottom-third 1963,1996 5 45.6 47.2 -1.6 26 52 1977 2022 2010 2013 bottom-third 1975,1985 6 50.9 52.4 -1.5 24 54 1977 2022 2010 2013 bottom-third 1960,2009 7 54.8 56.3 -1.5 23 54 1977 1955 2010 2013 bottom-third 1985,1996 8 57.4 58.7 -1.3 27 50 1977 1955 2010 2013 normal 1984 9 58.2 59.5 -1.3 27 50 1977 2002,2013 2010 2013 normal 1961,1980 10 57.5 59.2 -1.7 21 56 1962 2002,2013 2010 2013 bottom-third 1967,1983 11 55.9 57.9 -2.0 18 59 1962 2013 2010 2013 bottom-third 1996 12 54.1 56.1 -2.0 18 59 1979 2013 1997 2013 bottom-third 1949 18 53.8 54.8 -1.0 35 42 1979 2013 2011 2013 normal 1953,1991,2011 24 56.9 56.0 0.9 66 10 1962 2013 2012 2013 top-third 1989,1992 36 57.0 56.0 1.0 68 7 1963 2013 2012 2013 top-tenth 48 56.8 56.0 0.8 70 4 1962 2002 2013 2013 top-tenth 2008,2013 60 56.3 56.0 0.3 59 14 1963 2003 2013 2013 top-third 1992,2005,2009,2013,2022