1991-2020 Degrees Fahrenheit 1 57.5 62.1 -4.6 4 70 1951 1988 1998 2008 bottom-tenth 2 54.4 57.2 -2.8 5 69 1967 1988 2004 2008 bottom-tenth 1982,2004 3 48.8 52.0 -3.2 8 66 1950 1988 1982 2008 bottom-third 1951 4 42.2 46.5 -4.3 8 66 1950 1988 2002 2008 bottom-third 1953 5 36.4 41.0 -4.6 8 66 1950 1988 1982 2008 bottom-third 2011 6 32.6 36.8 -4.2 13 61 1950 1987 1982 2008 bottom-third 1969 7 29.2 34.4 -5.2 8 65 1950 1987 1982 2008 bottom-third 1972 8 29.5 33.8 -4.3 12 61 1979 2012 1982 2008 bottom-third 1969 9 31.1 34.9 -3.8 11 62 1979 2012 1982 2008 bottom-third 10 33.7 37.2 -3.5 11 62 1950 2012 1982 2008 bottom-third 1960 11 37.0 40.0 -3.0 13 60 1950,1979 2012 1982 2008 bottom-third 1949,2011 12 39.8 42.4 -2.6 20 53 1979 2012 1997 2008 bottom-third 1959 18 38.7 40.5 -1.8 26 46 1951 1988 1997 2008 normal 24 41.5 42.3 -0.8 37 34 1951 1988 1997 2008 normal 1954 36 42.4 42.3 0.1 50 19 1952 2000 2004 2008 top-third 2004 48 42.9 42.3 0.6 56 11 1952 1990,2008 2005 2008 top-third 1988,1989,1993,2022 60 43.0 42.4 0.6 58 7 1953 1992 2006 2008 top-third 2003,2006