1991-2020 Degrees Fahrenheit 1 38.6 33.5 5.1 76 8 1977 1950,2023 2001 1998 top-tenth 2 40.9 36.1 4.8 82 2 1977 2016 2001 2002 top-tenth 3 44.7 39.8 4.9 81 2 1977 2016 2001 2002 top-tenth 4 48.2 44.3 3.9 81 2 1977 2016 2001 2002 top-tenth 5 52.1 49.4 2.7 81 2 1977 2016 2001 2002 top-tenth 6 56.6 53.9 2.7 81 2 1977 2016 2001 2002 top-tenth 7 59.2 57.4 1.8 76 7 1977 2016 2001 2002 top-tenth 8 61.2 59.4 1.8 75 7 1977 2016 2001 2002 top-tenth 9 61.5 59.9 1.6 78 4 1977 2016 2001 2002 top-tenth 2017,2020 10 60.8 59.4 1.4 77 5 1977 2016 2001 2002 top-tenth 2007 11 58.9 57.9 1.0 70 11 1977 2016 2001 1999 top-third 1999 12 57.1 56.1 1.0 70 11 1968 2013 2001 1999 top-third 1950 18 55.0 55.3 -0.3 57 23 1978 2017 2001 2000 top-third 1972,1974,2014 24 55.8 56.0 -0.2 55 23 1945,1964,1969 2013 2001 2000 top-third 1955 36 56.0 56.0 0.0 59 16 1970 2023 1999 2001 top-third 2011,2015 48 56.3 55.9 0.4 59 13 1964 2023 2001 2002 top-third 2016 60 56.1 55.9 0.2 52 17 1970 2023 2001 2002 top-third 2007,2008