1991-2020 Degrees Fahrenheit 1 67.6 65.3 2.3 79 15 1973 2011 2002 2000 top-third 2 62.5 61.1 1.4 77 17 1958 2011 2002 2000 top-third 3 57.3 57.2 0.1 72 22 1958 2017 2002 2000 top-third 4 54.1 54.0 0.1 71 21 1958 2017 2002 2000 top-third 1990 5 52.2 52.3 -0.1 66 26 1973 2017 2002 2000 top-third 1976 6 51.8 52.4 -0.6 58 34 1973 2017 2002 2000 normal 1938,1996 7 53.4 54.3 -0.9 53 39 1977 2017 2001 2002 normal 1946,1990,2005,2015 8 56.2 56.9 -0.7 55 37 1977 2017 2001 2002 normal 9 59.5 59.7 -0.2 66 26 1977 2017 2002 2000 top-third 1978,2009 10 61.9 62.1 -0.2 68 24 1977 2017 2001 2002 top-third 1938,1950,1953,1974 11 63.7 63.8 -0.1 70 22 1977 2017 2001 2002 top-third 1953,1955,2019 12 64.6 64.7 -0.1 68 23 1977 2017 2001 2002 top-third 1957 18 60.3 60.6 -0.3 69 21 1977 2017 2002 2001 top-third 1952,1953,2014 24 64.9 64.7 0.2 74 15 1977 2000 2002 2001 top-third 36 64.6 64.6 0.0 69 18 1977 2018 1998 2002 top-third 2005 48 65.0 64.6 0.4 72 13 1977 2019,2020 1999 2002 top-third 2012,2015 60 65.5 64.5 1.0 79 4 1977 2020 2002 2003 top-tenth 2019