1991-2020 Degrees Fahrenheit 1 14.2 12.2 2.0 66 25 1983 2015 1910 1911 top-third 2 15.2 19.4 -4.2 31 58 1919 2001 1910 1911 normal 3 23.8 26.8 -3.0 28 60 1919 2015 1910 1911 bottom-third 4 30.8 33.8 -3.0 24 62 1919 2015 1911 1910 bottom-third 1988 5 36.6 39.7 -3.1 15 70 1919 2015 1911 1910 bottom-third 6 41.2 44.0 -2.8 12 73 1919 2015 1911 1910 bottom-third 1955 7 44.8 46.4 -1.6 25 58 1985 2021 1911 1910 bottom-third 1949,1957,1979 8 46.0 47.1 -1.1 38 45 1950 2021 1910 1911 normal 1970,1990,2000 9 45.1 46.1 -1.0 36 47 1950 2021 1911 1910 normal 1961,1990 10 43.3 43.9 -0.6 49 32 1950 2021 1911 1911 normal 1952,2018 11 40.5 40.8 -0.3 53 28 1950 1987,1998 1911 1911 normal 1920,1983,1984,2017 12 36.7 37.9 -1.2 44 37 1950 1998 1911 1911 normal 1920 18 38.4 39.9 -1.5 37 42 1950 2012 1911 1911 normal 24 -99 37.9 -99 -99 -99 1951 1999 normal 36 -99 37.8 -99 -99 -99 1951 2000 normal 48 -99 37.8 -99 -99 -99 1951 2001 normal 60 -99 37.7 -99 -99 -99 1952 2002 normal