1991-2020 Degrees Fahrenheit 1 51.1 51.4 -0.3 40 36 1972 2017 1958 1956 normal 2 58.1 57.1 1.0 64 12 1972 2017 1958 1953 top-third 3 62.6 61.5 1.1 64 12 1972 2017 1958 1949 top-third 2011,2015 4 64.8 64.0 0.8 60 16 1962 1949,2007,2016,2017 1958 1955 top-third 5 64.6 64.4 0.2 51 25 1958 1949 1958 1955 top-third 6 63.9 63.3 0.6 59 16 1958 1949 1958 1955 top-third 2005 7 61.6 60.9 0.7 59 15 1972 1949,2010 1958 1955 top-third 8 57.9 57.8 0.1 55 19 1972 2010,2012 1958 1955 top-third 2008 9 53.9 54.4 -0.5 43 31 1972 2012 1958 1957 normal 1951,1976,2000 10 50.9 51.6 -0.7 42 31 1978 2012 1958 1955 normal 2000 11 48.2 49.7 -1.5 22 51 1978 2012 1958 1957 bottom-third 1981,1994,2009 12 47.7 49.0 -1.3 27 46 1956,1978 2012 1958 1957 normal 1974,1987 18 51.8 53.8 -2.0 5 67 1978 2012 1959 1958 bottom-tenth 24 47.3 49.0 -1.7 12 58 1978 2017 1957 1958 bottom-third 2004 36 47.6 49.0 -1.4 15 52 1972 2012 1958 1957 bottom-third 1974,1977,1983,1994 48 47.2 49.0 -1.8 6 58 1965,1972 2013 1959 1958 bottom-tenth 1971,1978 60 47.6 48.9 -1.3 12 49 1966 2020 1959 1958 bottom-third 1975