1991-2020 Degrees Fahrenheit 1 40.1 41.2 -1.1 32 44 1967 2011 1976 1977 normal 2 44.7 46.3 -1.6 20 56 1972 1963 1976 1977 bottom-third 1952,1988 3 49.3 51.8 -2.5 10 66 1972 2011 1976 1977 bottom-third 1997 4 54.2 56.4 -2.2 9 67 1972 2011 1976 1977 bottom-third 5 57.2 59.5 -2.3 6 70 1976 2011 1976 1977 bottom-tenth 1987 6 58.5 60.6 -2.1 7 69 1986 2020 1976 1977 bottom-tenth 7 58.4 60.1 -1.7 10 65 1986 2015 1976 1977 bottom-third 1987,1996,2000 8 56.5 58.5 -2.0 7 67 1972 2010 1972 1977 bottom-tenth 9 53.7 55.9 -2.2 4 70 1972 2010 1972 1977 bottom-tenth 10 50.4 53.1 -2.7 2 72 1972 2012 1972 1977 bottom-tenth 11 47.8 50.6 -2.8 1 72 1972,1978 2012 1972 1977 lowest 1972 12 46.1 49.0 -2.9 1 72 1978 2012 1978 1977 lowest 18 50.5 52.9 -2.4 1 72 1978 2012 1978 1977 lowest 24 46.7 49.0 -2.3 1 69 1972,1978 2017 1972 1977 lowest 1972 36 47.0 49.0 -2.0 2 65 1972 2012,2022 1972 1977 bottom-tenth 48 47.4 48.9 -1.5 6 58 1965,1972 2013 1973 1977 bottom-tenth 1962,1971,1973 60 47.5 48.9 -1.4 7 54 1965 2020 1974 1977 bottom-third 1960,1973,1974