1991-2020 Degrees Fahrenheit 1 80.6 78.1 2.5 66 12 1992 2000 2005 2003 top-third 2 81.5 79.1 2.4 66 11 1950 1980 2005 2003 top-third 2012 3 79.8 78.0 1.8 70 7 1950 2011 2005 1980 top-tenth 2018 4 76.5 75.0 1.5 67 10 1967 2018 2005 2000 top-third 1952,2022 5 73.4 71.2 2.2 73 4 1950 2012 2005 2006 top-tenth 6 69.0 66.9 2.1 75 2 1950,1960 2012 2005 2006 top-tenth 2010 7 64.1 62.4 1.7 70 7 1960 2012 2005 2000 top-tenth 8 61.3 58.4 2.9 75 2 1979 2012 2005 2006 top-tenth 9 57.8 55.7 2.1 73 4 1979 2012 2005 2000 top-tenth 10 56.7 54.6 2.1 73 4 1979 2012 2005 2000 top-tenth 11 56.9 54.8 2.1 73 4 1979 2012 2005 2000 top-tenth 12 58.2 56.1 2.1 73 4 1979 2012 2005 2000 top-tenth 18 61.2 59.7 1.5 73 3 1979 2012 2005 2006 top-tenth 2016 24 57.6 56.0 1.6 72 4 1979 2017 2005 2000 top-tenth 36 56.7 56.0 0.7 65 10 1979 2018 2005 2002 top-third 48 56.5 56.0 0.5 65 9 1961,1962,1980 2002 2005 2003 top-third 2012,2017 60 56.7 56.0 0.7 69 4 1962 2002 2005 2003 top-tenth