1991-2020 Degrees Fahrenheit 1 52.1 57.0 -4.9 4 74 1976 1963 2009 2018 bottom-tenth 2 64.2 63.0 1.2 56 22 2009 1963 2018 2017 top-third 3 68.3 68.0 0.3 53 25 1967 1947 2017 2018 top-third 4 71.1 70.9 0.2 51 26 1967 1954 2017 2018 normal 1995 5 71.9 71.8 0.1 50 27 1967 1954 2017 2018 normal 1971,2017 6 70.6 70.8 -0.2 47 30 1967 2018 2009 2018 normal 7 68.8 68.6 0.2 53 24 1961 2012 2013 2018 top-third 8 65.3 65.7 -0.4 46 31 1951 2012 2013 2018 normal 9 61.3 62.2 -0.9 42 35 1960 2012 2013 2018 normal 10 58.1 59.0 -0.9 41 36 1979 2012 2014 2018 normal 2014 11 56.1 56.7 -0.6 45 32 1979 2012 2014 2018 normal 12 54.6 55.7 -1.1 41 36 1979 2012 2014 2018 normal 1947,1976 18 60.9 60.7 0.2 59 17 1951,1979 2012 2015 2018 top-third 24 55.5 55.6 -0.1 55 21 1979 2017 2015 2018 top-third 1988 36 56.2 55.6 0.6 65 10 1979 2018 2016 2018 top-third 2001,2016 48 56.8 55.6 1.2 72 2 1951,1962 2018 2017 2018 top-tenth 2013 60 56.5 55.6 0.9 70 3 1962 2016 2018 2018 top-tenth 2018