1991-2020 Degrees Fahrenheit 1 34.4 34.8 -0.4 47 31 1979 2017 2011 2012 normal 2 34.4 32.5 1.9 61 17 1979 1992 2011 2012 top-third 3 35.1 32.8 2.3 67 11 1979 1992 2011 2012 top-third 4 38.3 35.6 2.7 70 8 1979 2000 2011 2012 top-tenth 2022 5 41.7 39.9 1.8 68 10 1979 2017 2011 2012 top-third 2006 6 46.1 44.8 1.3 65 13 1979 2017 2011 2012 top-third 2020 7 50.5 49.5 1.0 66 12 1979 2017 2011 2012 top-third 2020 8 55.0 53.3 1.7 69 8 1979 2017 2011 2012 top-tenth 2023 9 57.6 55.7 1.9 70 7 1979 2017 2011 2012 top-tenth 10 59.0 56.7 2.3 73 4 1977 2017 2011 2012 top-tenth 11 59.1 56.6 2.5 75 2 1962 2017 2012 2012 top-tenth 2012 12 59.2 55.7 3.5 76 1 1962 2013 2012 2013 highest 18 55.1 52.0 3.1 75 2 1979 2017 2012 2013 top-tenth 24 58.5 55.6 2.9 75 1 1962,1963 2013 2012 2013 highest 36 57.8 55.6 2.2 74 1 1979 2013 2012 2013 highest 48 56.6 55.6 1.0 70 4 1962,1980 2019 2012 2013 top-tenth 2020 60 56.2 55.6 0.6 65 8 1963 2017,2020 2012 2003 top-third 2003,2018