1991-2020 Degrees Fahrenheit 1 11.3 19.9 -8.6 13 63 2019 1954 2001 2009 bottom-third 2 12.0 18.3 -6.3 18 58 1950 1992 1994 2009 bottom-third 1963 3 10.8 19.0 -8.2 11 64 1950 1992 1982 2009 bottom-third 4 17.4 21.9 -4.5 23 52 1979 2000 2009 2008 bottom-third 5 21.2 26.4 -5.2 12 63 1979 2000 1997 2009 bottom-third 1959,1997 6 28.3 31.8 -3.5 23 52 1952 1998 1997 2009 bottom-third 1985 7 33.6 37.1 -3.5 19 56 1978 1998 1997 2009 bottom-third 1959 8 37.3 41.2 -3.9 13 62 1952 1999 1994 2009 bottom-third 9 39.6 43.6 -4.0 6 68 1952 1998 1994 2009 bottom-tenth 1965,1972 10 40.8 44.5 -3.7 5 69 1952 1998 1994 2009 bottom-tenth 1969,1978 11 40.6 44.3 -3.7 4 70 1952 1981,1999 1994 2009 bottom-tenth 12 39.1 43.2 -4.1 4 70 1952 2016 1966 2009 bottom-tenth 18 35.5 39.4 -3.9 5 68 1952 2000 1979 2009 bottom-tenth 24 40.3 43.2 -2.9 7 65 1952 2000 1997 2009 bottom-tenth 1994,1997 36 41.7 43.2 -1.5 21 49 1952 2000 1980 2009 bottom-third 1960,2020 48 42.4 43.3 -0.9 35 33 1953 1992,2002 1997 2009 normal 2013 60 42.8 43.4 -0.6 40 26 1954 2002 1998 2009 normal 1964,1983,2023