1991-2020 Degrees Fahrenheit 1 34.7 38.2 -3.5 22 72 1909 1987 2013 2012 bottom-third 1967,1989 2 23.9 31.0 -7.1 8 84 1950 2010 2013 2012 bottom-tenth 3 15.9 24.0 -8.1 4 88 1917,1923 2012 1989 2013 bottom-tenth 4 11.1 19.3 -8.2 6 86 1950 2012 1996 2013 bottom-tenth 5 8.1 17.6 -9.5 1 89 2014 2012 2014 2013 lowest 6 10.9 19.1 -8.2 4 84 1996 2012 1996 2013 bottom-tenth 7 15.3 22.3 -7.0 3 84 1920 2012 1996 2013 bottom-tenth 1979 8 20.6 26.3 -5.7 6 79 1920 2012 1996 2013 bottom-tenth 9 25.3 30.4 -5.1 6 78 1920 2012 1996 2013 bottom-tenth 10 29.3 33.8 -4.5 6 78 1920 2012 1996 2013 bottom-tenth 1950 11 32.1 36.3 -4.2 5 77 1951 2012 1996 2013 bottom-tenth 1996 12 33.6 37.5 -3.9 4 78 1951 2012 1996 2013 bottom-tenth 1979,1996 18 27.8 31.3 -3.5 14 65 1951 1999,2017 1997 2013 bottom-third 24 34.9 37.4 -2.5 15 62 1951 2017 1997 2013 bottom-third 1970 36 37.2 37.4 -0.2 56 16 1952 2000 2011 2013 top-third 1992 48 37.2 37.4 -0.2 51 16 1952,1953 2001 2011 2013 top-third 60 37.4 37.3 0.1 48 15 1970 2002 2011 2013 top-third 2018