1991-2020 Degrees Fahrenheit 1 58.6 62.1 -3.5 8 66 1951 1988 1951 1953 bottom-third 2 54.1 57.2 -3.1 4 70 1967 1988 1950 1953 bottom-tenth 3 48.3 52.0 -3.7 5 69 1950 1988 1953 1952 bottom-tenth 4 41.0 46.5 -5.5 3 71 1950 1988 1951 1953 bottom-tenth 5 39.4 41.0 -1.6 32 42 1950 1988 1953 1952 normal 1956,2022 6 33.3 36.8 -3.5 20 54 1950 1987 1951 1953 bottom-third 7 31.7 34.4 -2.7 25 48 1950 1987 1952 1953 normal 8 32.2 33.8 -1.6 32 41 1979 2012 1952 1953 normal 9 34.3 34.9 -0.6 41 32 1979 2012 1953 1954 normal 2004 10 36.5 37.2 -0.7 41 32 1950 2012 1953 1954 normal 2004 11 39.3 40.0 -0.7 41 32 1950,1979 2012 1953 1954 normal 1958 12 41.7 42.4 -0.7 38 35 1979 2012 1953 1954 normal 18 39.4 40.5 -1.1 36 36 1951 1988 1953 1954 normal 2020 24 41.5 42.3 -0.8 37 34 1951 1988 1953 1954 normal 2009 36 40.2 42.3 -2.1 11 58 1952 2000 1953 1954 bottom-third 1957,1966,1995 48 39.4 42.3 -2.9 3 64 1952 1990,2008 1953 1954 bottom-tenth 60 38.9 42.4 -3.5 2 63 1953 1992 1953 1954 bottom-tenth