1991-2020 Degrees Fahrenheit 1 57.8 55.4 2.4 63 14 2018 1955 2018 2016 top-third 2 49.6 50.4 -0.8 43 34 1960 2012 2018 2017 normal 1968,1973 3 42.7 45.2 -2.5 27 50 1960 2012 2018 2017 normal 1952,1961 4 39.4 41.5 -2.1 37 40 1979 2012 2018 2017 normal 5 38.7 39.9 -1.2 44 33 1979 2012 2018 2017 normal 6 38.5 40.6 -2.1 31 46 1979 2012 2014 2018 normal 1950,1961,1968,1994 7 40.9 42.9 -2.0 30 47 1979 2012 2014 2018 normal 2010 8 44.7 46.2 -1.5 33 44 1979 2012 2014 2018 normal 1985,1990 9 48.5 49.7 -1.2 36 41 1979 2012 2014 2018 normal 1953,1961,1974,1988 10 51.7 52.7 -1.0 41 35 1979 2012 2014 2018 normal 1948,2001 11 54.3 54.8 -0.5 48 28 1962,1979 2012 2018 2017 normal 1953,1957 12 56.0 55.7 0.3 59 17 1962 2012 2018 2017 top-third 1991 18 50.4 50.6 -0.2 55 21 1979 2017 2015 2018 top-third 1987,1988,2011 24 55.5 55.6 -0.1 54 21 1979 2017 2015 2018 top-third 36 56.5 55.6 0.9 69 5 1979 2017 2016 2018 top-tenth 2001 48 56.9 55.6 1.3 72 1 1980 2019 2018 2019 highest 60 56.6 55.6 1.0 69 3 1962 2016,2020 2018 2017 top-tenth 2017