1991-2020 Degrees Fahrenheit 1 21.8 28.1 -6.3 16 84 1977 1932 2004 2013 bottom-third 2 26.4 30.6 -4.2 28 72 1977 1932 2011 2013 bottom-third 1962,2004 3 30.8 34.4 -3.6 23 75 1977 1932 2011 2013 bottom-third 4 36.8 39.0 -2.2 38 59 1977 1932 2011 2013 normal 1987 5 41.9 44.1 -2.2 32 65 1977 1932 2009 2013 bottom-third 1965,1973,1987 6 46.5 48.6 -2.1 31 66 1977 1932 2009 2013 bottom-third 1957,1973,1993 7 50.8 52.2 -1.4 48 49 1977 1932 2009 2013 normal 1976 8 53.2 54.3 -1.1 57 40 1977 2016 2010 2013 normal 2005 9 53.9 54.9 -1.0 61 36 1977 2016 2010 2013 normal 10 53.6 54.4 -0.8 70 27 1925 2016 2010 2013 top-third 1953,1958,1985 11 52.0 53.0 -1.0 63 34 1925 2012,2013,2020,2021,2023 2009 2013 normal 1953,1956 12 50.2 51.1 -0.9 65 32 1925 2021 2009 2013 top-third 1985 18 50.0 50.2 -0.2 71 22 1941 2017 2010 2013 top-third 2009 24 51.9 51.0 0.9 81 12 1926 2021 2011 2013 top-third 36 52.3 51.0 1.3 81 8 1970 2022,2023 2012 2013 top-tenth 48 52.1 50.9 1.2 80 6 1971 2023 2013 2013 top-tenth 2013 60 51.7 50.9 0.8 76 7 1944,1945,1965,1968,1971 2023 2013 2013 top-tenth 2013,2016