1991-2020 Degrees Fahrenheit 1 91.5 88.7 2.8 61 7 1965 2021 2012 2006 top-tenth 2 86.5 84.3 2.2 63 5 1965 2001,2006 2011 2012 top-tenth 2021 3 82.4 80.3 2.1 65 3 1967,1975 2000 2012 2012 top-tenth 2012 4 79.2 76.8 2.4 66 2 1975 2004 2012 2004 top-tenth 5 74.8 73.5 1.3 59 9 1975 2014,2015,2016,2017 2012 2004 top-third 6 71.2 70.8 0.4 50 16 1975 2014 2011 2012 top-third 1981 7 69.0 68.7 0.3 47 15 1975 2015 2012 2012 top-third 2012,2021 8 68.7 68.1 0.6 51 11 1975 1996 2012 2000 top-third 9 69.7 69.1 0.6 49 12 1975 1996,2015 2012 2004 top-third 10 71.8 71.0 0.8 51 10 1973 1996 2012 2004 top-third 2021 11 73.8 73.1 0.7 50 11 1973 1996 2011 2012 top-third 2014 12 75.4 74.9 0.5 49 12 1975 1996 2011 2012 top-third 18 74.2 73.5 0.7 52 8 1976 2015 2012 1997 top-third 2021 24 75.6 74.9 0.7 49 7 1973,1975,1976 2018 2012 1997 top-third 36 75.0 74.9 0.1 41 10 1975,1977 2017,2018 2007 2004 top-third 2004,2021 48 -99 74.9 -99 -99 -99 1975,1976 2018 normal 60 -99 74.8 -99 -99 -99 1977 2018 normal