1991-2020 Degrees Fahrenheit 1 63.8 59.7 4.1 77 1 1964 1997 1996 1997 highest 2 61.3 58.4 2.9 76 2 1948 1992 1996 1992 top-tenth 3 59.6 57.4 2.2 73 5 1948 1992 1996 1992 top-tenth 4 58.1 56.4 1.7 72 5 1948 1992 1996 1992 top-tenth 5 56.9 55.4 1.5 72 5 1949 2016 1996 1992 top-tenth 1986 6 56.3 54.7 1.6 73 4 1949 2015 1995 1996 top-tenth 1992,2014 7 56.4 54.9 1.5 74 3 1949 2015 1995 1996 top-tenth 1992,2014 8 57.0 55.8 1.2 71 6 1949 2015 1995 1996 top-tenth 9 57.6 56.9 0.7 67 10 1949 2015 1995 1996 top-third 2004 10 58.3 57.6 0.7 66 11 1949 2015 1995 1996 top-third 2005,2017 11 58.9 58.2 0.7 67 9 1949 2015 1995 1996 top-third 2004,2005,2014 12 59.2 58.5 0.7 67 8 1949 2015 1995 1996 top-third 1993,2004,2014 18 58.3 57.2 1.1 69 5 1949,1950 2016 1996 1997 top-tenth 2017 24 59.6 58.4 1.2 68 5 1950 2016 1996 1997 top-tenth 2018 36 58.8 58.4 0.4 62 9 1950 2016,2017 1996 1994 top-third 48 58.8 58.4 0.4 65 4 1951,1952 2018 1996 1996 top-tenth 1996,2015 60 58.9 58.3 0.6 64 4 1952,1953 2018 1996 1997 top-tenth