1991-2020 Degrees Fahrenheit 1 33.1 34.7 -1.6 46 47 1960 2012 1932 1933 normal 2 24.2 28.5 -4.3 31 62 1936 2012 1932 1933 bottom-third 1958 3 24.9 25.0 -0.1 61 32 1936 2012 1932 1933 normal 1953,2009 4 22.6 24.3 -1.7 44 48 1936 2012 1933 1933 normal 1957,1974 5 24.4 26.3 -1.9 38 54 1936 2012 1933 1933 normal 6 28.0 30.3 -2.3 34 58 1936 2012 1933 1933 normal 2010 7 32.6 35.0 -2.4 30 61 1936 2012 1933 1933 bottom-third 8 37.4 39.7 -2.3 27 64 1936 2012 1933 1933 bottom-third 1949 9 41.7 43.5 -1.8 30 61 1936 2012 1933 1933 bottom-third 1959,1996 10 44.6 46.1 -1.5 34 57 1936 2012 1933 1933 normal 1984 11 46.1 47.3 -1.2 37 54 1936 2012 1933 1933 normal 1967 12 46.3 47.3 -1.0 38 53 1936 2012 1933 1933 normal 1941,1977 18 -99 41.6 -99 -99 -99 1979 2017 normal 24 -99 47.3 -99 -99 -99 1952 2017 normal 36 -99 47.3 -99 -99 -99 1952 2017,2018 normal 48 -99 47.4 -99 -99 -99 1952 2018 normal 60 -99 47.4 -99 -99 -99 1952 2006 normal