1991-2020 Degrees Fahrenheit 1 81.4 81.1 0.3 60 16 1967 2011 2013 2011 top-third 2 80.3 81.2 -0.9 42 34 1967 2000 2013 2012 normal 1962,1991,2001 3 79.5 80.5 -1.0 32 44 1961 2011 1997 2013 normal 1957 4 77.4 78.8 -1.4 25 51 1961 2010,2019 1997 2013 bottom-third 1949,1959,1975 5 75.0 76.3 -1.3 23 53 1961 2011 1997 2013 bottom-third 1964 6 71.7 73.6 -1.9 12 64 1961,1983 2011 1996 2013 bottom-third 1956,1996 7 69.0 70.8 -1.8 21 55 1958 2018,2019 1996 2013 bottom-third 1965 8 65.6 68.3 -2.7 11 65 1958 2012 1984 2013 bottom-third 1970,1984 9 64.2 66.5 -2.3 14 61 1978 2017 1984 2013 bottom-third 10 63.4 65.7 -2.3 11 64 1969,1978 2017 1984 2013 bottom-third 1971,1973,1983 11 64.0 65.9 -1.9 19 56 1977 2017 1996 2013 bottom-third 1963 12 65.2 66.9 -1.7 21 54 1977 2017 1996 2013 bottom-third 1951,1967,1980,1994 18 67.4 69.1 -1.7 19 56 1977,1984 2017 1994 2013 bottom-third 1963,1965,1983 24 65.7 66.8 -1.1 30 44 1978 2017,2020 1997 2013 normal 1956 36 66.6 66.8 -0.2 56 17 1970,1978,1979 2019 2011 2013 top-third 48 66.7 66.7 0.0 56 16 1961,1971 2020 2011 2013 top-third 2005 60 66.5 66.7 -0.2 52 19 1970 2020 2011 2013 top-third 1999,2004,2010,2011