1991-2020 Degrees Fahrenheit 1 72.3 72.9 -0.6 35 40 1954 1962 2016 2015 normal 2 70.5 68.7 1.8 65 10 1961,1997 1955 2016 2015 top-third 2011 3 66.8 65.1 1.7 68 7 1971 2012 2016 2015 top-tenth 1995 4 64.5 61.6 2.9 73 2 1971 2012 2016 2012 top-tenth 5 62.5 58.9 3.6 73 1 1978 2017 2016 2017 highest 6 60.9 57.4 3.5 73 1 1978 2017 2016 2017 highest 7 60.6 57.2 3.4 72 1 1977 2017 2016 2017 highest 8 61.7 58.3 3.4 72 1 1977 2017 2016 2017 highest 9 63.6 60.3 3.3 72 1 1968 2017 2016 2017 highest 10 65.6 62.4 3.2 72 1 1968 2017 2016 2017 highest 11 67.4 64.3 3.1 72 1 1968 2017 2016 2017 highest 12 68.6 65.5 3.1 72 1 1968 2017 2016 2017 highest 18 65.4 62.8 2.6 71 1 1970 2017 2016 2017 highest 24 67.8 65.5 2.3 70 1 1969 2017 2016 2017 highest 36 66.8 65.5 1.3 66 3 1970 2018 2016 2017 top-tenth 48 66.0 65.4 0.6 61 6 1971 2020 2016 2017 top-tenth 60 65.8 65.4 0.4 59 6 1970 2020 2016 2017 top-tenth