1991-2020 Degrees Fahrenheit 1 63.8 63.3 0.5 47 29 1997 2018 2011 2013 normal 2 59.2 58.2 1.0 54 22 1997 1991 2011 2013 top-third 3 51.9 52.7 -0.8 33 43 1984 2012 2008 2013 normal 1962,2020 4 45.3 47.6 -2.3 15 61 1978 2012 1996 2013 bottom-third 1994 5 40.7 44.1 -3.4 5 71 1978 2012,2017 1994 2013 bottom-tenth 2015 6 39.7 42.5 -2.8 7 68 1978 2012 1996 2013 bottom-tenth 1961 7 39.8 42.6 -2.8 7 68 1978 2012 1996 2013 bottom-tenth 1951,1994 8 41.8 44.2 -2.4 10 65 1978 2012 1996 2013 bottom-third 1970 9 44.7 46.7 -2.0 11 64 1978 2017 1996 2013 bottom-third 1951,1958 10 47.5 49.5 -2.0 11 64 1977,1978 2017 1996 2013 bottom-third 1984 11 50.0 51.8 -1.8 11 64 1977 2017 1996 2013 bottom-third 1993 12 51.8 53.5 -1.7 12 63 1977 2017 1996 2013 bottom-third 18 48.8 49.8 -1.0 27 47 1979 2017 2010 2013 normal 1981,1990,2010 24 52.8 53.4 -0.6 34 40 1978 2017 2011 2013 normal 1966,1989 36 54.0 53.4 0.6 62 11 1979 2018 2012 2013 top-third 48 53.7 53.4 0.3 61 11 1980 2019 2012 2013 top-third 1957,2000,2001,2008,2012,2017 60 53.5 53.4 0.1 54 17 1981 2020 2011 2013 top-third 1976,2008