1991-2020 Degrees Fahrenheit 1 62.8 60.0 2.8 73 5 1964 1997 2013 2001 top-tenth 2 60.9 58.8 2.1 75 3 1964 1992 2013 1997 top-tenth 3 60.1 57.8 2.3 76 2 1948 1992 2013 2004 top-tenth 1997,2004 4 58.8 56.8 2.0 74 3 1948 1992 2013 1992 top-tenth 2015 5 57.9 55.7 2.2 76 1 1949 2014,2015,2016 2013 2014 highest 2015,2016 6 56.6 55.0 1.6 73 4 1949 2015 2013 1997 top-tenth 1996,1997 7 56.7 55.2 1.5 73 4 1949 2015 2013 1996 top-tenth 8 57.1 56.2 0.9 69 8 1949 2015 2013 1997 top-tenth 2021 9 58.1 57.2 0.9 68 9 1949 2015 2013 1996 top-third 10 58.8 58.0 0.8 68 9 1949 2015 2013 2004 top-third 2004 11 59.2 58.6 0.6 65 11 1949 2015 2013 2005 top-third 1993,1997 12 59.5 58.9 0.6 64 11 1949 2015 2013 2005 top-third 2005 18 57.9 57.6 0.3 60 14 1949,1950 2015,2016 2013 2005 top-third 1988 24 58.9 58.8 0.1 59 14 1950 2016 2013 2006 top-third 1988,1992,2006 36 58.5 58.8 -0.3 51 20 1950 2016 2013 2011 top-third 1990,1992 48 58.5 58.8 -0.3 50 19 1951,1952,1955,1956 2018 2013 2007 top-third 1990,1991,1992 60 58.5 58.7 -0.2 49 19 1952,1953,1956 2018 2013 2008 top-third 1987,1989,1990,1991,1999