1991-2020 Degrees Fahrenheit 1 5.1 19.9 -14.8 2 74 2019 1954 1949 1949 bottom-tenth 2 3.0 18.3 -15.3 2 74 1950 1992 1949 1949 bottom-tenth 3 6.2 19.0 -12.8 3 72 1950 1992 1949 1949 bottom-tenth 4 12.2 21.9 -9.7 4 71 1979 2000 1949 1949 bottom-tenth 5 18.9 26.4 -7.5 3 72 1979 2000 1949 1949 bottom-tenth 1952 6 26.4 31.8 -5.4 8 67 1952 1998 1949 1949 bottom-third 1994 7 32.6 37.1 -4.5 11 64 1978 1998 1949 1949 bottom-third 8 37.1 41.2 -4.1 10 65 1952 1999 1949 1949 bottom-third 1956 9 -99 43.6 -99 -99 -99 1952 1998 normal 10 -99 44.5 -99 -99 -99 1952 1998 normal 11 -99 44.3 -99 -99 -99 1952 1981,1999 normal 12 -99 43.2 -99 -99 -99 1952 2016 normal 18 -99 39.4 -99 -99 -99 1952 2000 normal 24 -99 43.2 -99 -99 -99 1952 2000 normal 36 -99 43.2 -99 -99 -99 1952 2000 normal 48 -99 43.3 -99 -99 -99 1953 1992,2002 normal 60 -99 43.4 -99 -99 -99 1954 2002 normal