1991-2020 Degrees Fahrenheit 1 41.5 40.2 1.3 69 16 1989 2015 1997 1998 top-third 2 46.8 44.7 2.1 75 10 1989 2015 1997 1998 top-third 3 50.6 49.6 1.0 70 15 1976,1980 2015 1997 1998 top-third 4 55.7 54.9 0.8 70 14 1976 2015 1997 1998 top-third 5 60.0 59.5 0.5 70 14 1962,1976 2015 1997 1998 top-third 2018 6 63.8 62.8 1.0 75 9 1962 2015 1997 1998 top-third 7 65.3 64.3 1.0 76 8 1962 2015 1998 1999 top-tenth 8 65.1 64.2 0.9 75 9 1940,1958,1962 2015 1998 1991 top-third 1991 9 63.9 63.0 0.9 75 9 1940 2015 1998 1991 top-third 10 61.8 61.1 0.7 73 11 1940 2010,2016 1997 1998 top-third 11 59.7 58.8 0.9 75 9 1940 2016 1997 1998 top-third 2001 12 57.6 56.8 0.8 72 12 1940 2012,2016 1997 1998 top-third 1953,2002 18 59.7 58.8 0.9 74 9 1963 2016 1998 1991 top-third 24 58.1 56.8 1.3 80 3 1941 2021 1998 1999 top-tenth 36 57.3 56.8 0.5 74 8 1942 2022 1998 1999 top-tenth 2013,2020 48 56.8 56.7 0.1 67 14 1943 2018 1998 1999 top-third 2000,2010 60 56.7 56.7 0.0 61 19 1944 2020 1998 1999 top-third 2003,2005,2015