1991-2020 Degrees Fahrenheit 1 63.1 64.6 -1.6 34 62 1953 2015 1928 1928 normal 2 61.8 61.3 0.5 68 28 1953 2015 1928 1928 top-third 1993 3 57.1 57.5 -0.4 54 42 2011 1992 1928 1928 normal 1941,1951,1973 4 54.2 54.2 0.0 64 32 1955 2015 1928 1928 top-third 1938,1961 5 50.2 51.0 -0.8 54 42 1955 2015 1928 1928 normal 1938,1957,1966,2008 6 46.4 48.3 -1.9 36 60 1950 1934 1928 1928 normal 1991,1996 7 -99 46.2 -99 -99 -99 1950 1934 normal 8 -99 45.5 -99 -99 -99 1950 1934 normal 9 -99 46.2 -99 -99 -99 1950 1934 normal 10 -99 47.9 -99 -99 -99 1950 2015 normal 11 -99 50.1 -99 -99 -99 1950 2015 normal 12 -99 52.0 -99 -99 -99 1950 2015 normal 18 -99 50.8 -99 -99 -99 1930,1950 2016 normal 24 -99 52.0 -99 -99 -99 1950 2016 normal 36 -99 52.0 -99 -99 -99 1950 2016 normal 48 -99 52.0 -99 -99 -99 1932,1950,1952 2016 normal 60 -99 52.0 -99 -99 -99 1933 2016,2018 normal