1925-2000 Degrees Fahrenheit 1 -7.9 3.7 -11.6 4 95 1942 2017 1942 1960 bottom-tenth 2 0.4 7.7 -7.3 4 95 1956 2002 1956 1960 bottom-tenth 3 7.5 13.6 -6.1 2 97 1956 2002 1956 1960 bottom-tenth 4 15.9 20.4 -4.5 3 96 1956 2002 1956 1960 bottom-tenth 1975 5 22.4 26.2 -3.8 4 95 1956 2002 1956 1960 bottom-tenth 6 27.2 30.6 -3.4 3 96 1956 2002 1956 1960 bottom-tenth 7 30.2 33.3 -3.1 4 95 1956 2017,2019 1956 1960 bottom-tenth 1933 8 31.4 33.8 -2.4 6 93 1956 2019 1956 1960 bottom-tenth 9 30.2 32.7 -2.5 6 93 1955,1956 2019 1956 1960 bottom-tenth 10 27.5 30.5 -3.0 5 94 1956 2019 1956 1960 bottom-tenth 11 25.0 28.1 -3.1 3 96 1956 2019 1956 1960 bottom-tenth 12 23.7 26.0 -2.3 9 90 1956 2019 1956 1960 bottom-tenth 1974 18 26.3 27.5 -1.2 15 83 1956 2019 1956 1960 bottom-third 24 25.2 26.0 -0.8 18 80 1956 2019 1957 1960 bottom-third 1947 36 25.0 26.0 -1.0 16 81 1956 2016 1957 1960 bottom-third 1935,1950 48 25.5 25.9 -0.4 27 69 1974 2019 1959 1960 bottom-third 1952,1962 60 26.1 25.9 0.2 36 59 1975 2019 1960 1947 normal 1931,1932,1939,1947,1986,2012