1991-2020 Degrees Fahrenheit 1 72.6 74.0 -1.4 33 43 1976 2020 2001 2002 normal 2 69.9 72.0 -2.1 21 54 1972 1991 2000 2002 bottom-third 3 66.4 68.5 -2.1 23 52 1961,1976,1979 1991 1997 2002 bottom-third 4 62.9 64.1 -1.2 33 42 1961 1991 2000 2002 normal 1957,1981,2000,2009 5 58.5 59.1 -0.6 44 31 1960 1991 2001 2002 normal 6 52.9 54.3 -1.4 33 42 1978 1991 1997 2002 normal 1964,1997 7 48.3 50.6 -2.3 21 54 1978 2012 1996 2002 bottom-third 2015 8 46.0 48.4 -2.4 20 55 1978 2012 1996 2002 bottom-third 1962,1965 9 45.4 47.8 -2.4 19 55 1978 2012 1996 2002 bottom-third 1962,1982 10 46.0 48.4 -2.4 20 54 1978 2012 1996 2002 bottom-third 1968 11 48.1 50.0 -1.9 24 50 1978 2012 1996 2002 bottom-third 1964 12 50.3 51.9 -1.6 30 44 1978 2012 1996 2002 normal 18 51.9 52.7 -0.8 46 27 1979 2012 1997 2002 normal 1983,1995 24 51.9 51.8 0.1 55 17 1978 2017 1998 2000 top-third 36 -99 51.7 -99 -99 -99 1979 2018 normal 48 -99 51.7 -99 -99 -99 1980 2019 normal 60 -99 51.6 -99 -99 -99 1981 2020 normal