1991-2020 Degrees Fahrenheit 1 8.1 10.0 -1.9 55 42 1917 1998 1923 1924 normal 1951 2 5.1 7.7 -2.6 50 45 1917 1998 1924 1922 normal 3 2.3 9.1 -6.8 21 70 1979 1998 1920 1924 bottom-third 4 -99 13.4 -99 -99 -99 1979 2002 normal 5 -99 19.1 -99 -99 -99 1920 2012 normal 6 -99 25.0 -99 -99 -99 1920 1998 normal 7 -99 30.5 -99 -99 -99 1920 2002 normal 8 -99 34.8 -99 -99 -99 1920 2002,2012 normal 9 -99 37.8 -99 -99 -99 1959 2002 normal 10 -99 39.2 -99 -99 -99 1951,1959 2002 normal 11 -99 39.1 -99 -99 -99 1951 2002 normal 12 -99 37.9 -99 -99 -99 1951 2002 normal 18 -99 33.6 -99 -99 -99 1951 2017 normal 24 -99 37.9 -99 -99 -99 1952 2017 normal 36 -99 37.8 -99 -99 -99 1952 2000 normal 48 -99 37.8 -99 -99 -99 1952 2002 normal 60 -99 37.7 -99 -99 -99 1953 2002 normal