1925-2000 Degrees Fahrenheit 1 -3.5 4.8 -8.3 12 88 1990 2016 1925 1925 bottom-third 2 -7.2 3.5 -10.7 1 99 1925 2016 1925 1925 lowest 3 -99 3.6 -99 -99 -99 1965 2001 normal 4 -99 5.6 -99 -99 -99 1956 2003 normal 5 -99 9.6 -99 -99 -99 1956 2003 normal 6 -99 14.8 -99 -99 -99 1956 2003 normal 7 -99 19.7 -99 -99 -99 1956 2003 normal 8 -99 23.9 -99 -99 -99 1956 2003 normal 9 -99 26.7 -99 -99 -99 1956 2003 normal 10 -99 27.8 -99 -99 -99 1956 2003 normal 11 -99 27.4 -99 -99 -99 1956 2016 normal 12 -99 26.0 -99 -99 -99 1956 2016 normal 18 -99 22.2 -99 -99 -99 1972 2016 normal 24 -99 26.0 -99 -99 -99 1957 2016,2017 normal 36 -99 25.9 -99 -99 -99 1973,1974 2017,2018 normal 48 -99 25.9 -99 -99 -99 1974 2019 normal 60 -99 25.9 -99 -99 -99 1976 2019,2020 normal