1991-2020 Degrees Fahrenheit 1 55.6 56.9 -1.3 28 39 1960 2003 2013 2018 normal 1991 2 55.3 56.0 -0.7 30 33 1972 2018 2016 2018 normal 2012 3 58.0 58.7 -0.7 34 29 1973 2018 2016 2018 normal 1968,1970 4 62.2 63.2 -1.0 28 34 1972 2018 2007 2018 normal 1986,1998 5 68.0 68.3 -0.3 40 22 1972 1996 2014 2018 normal 1997,2014 6 72.7 72.6 0.1 45 17 1973 1996 2014 2018 top-third 7 76.1 75.7 0.4 51 11 1972,1973 1996,2018 2016 2018 top-third 2003,2016 8 77.7 77.3 0.4 50 12 1972 2018 2014 2018 top-third 1978,2013 9 78.0 77.6 0.4 51 11 1972 2018 2016 2018 top-third 1997 10 77.8 77.1 0.7 56 6 1972 2018 2016 2018 top-tenth 2013 11 76.7 76.1 0.6 54 8 1972 2018 2013 2018 top-third 1997,2013 12 75.3 74.8 0.5 53 9 1972 2018 2014 2018 top-third 2013 18 75.1 74.1 1.0 51 6 1972 2018 2015 2018 top-tenth 24 76.1 74.9 1.2 54 3 1966 2018 2017 2018 top-tenth 2017 36 76.2 74.9 1.3 50 2 1972,1974 2018 2017 2018 top-tenth 2017 48 76.1 74.9 1.2 45 2 1968,1974 2018 2017 2018 top-tenth 60 76.2 74.8 1.4 41 1 1974,1976 2018,2019 2018 2018 highest 2018