1991-2020 Degrees Fahrenheit 1 18.4 18.9 -0.5 36 36 1977 2006 1952 1952 normal 2 18.7 21.6 -2.9 23 49 1977 2002 1952 1952 bottom-third 3 21.6 26.6 -5.0 11 61 1977 2002 1952 1952 bottom-third 1963 4 28.8 32.4 -3.6 10 62 1977 2002 1952 1952 bottom-third 5 34.7 38.4 -3.7 7 65 1977 2016 1952 1952 bottom-tenth 6 40.2 43.7 -3.5 4 67 1977 2002 1952 1952 bottom-tenth 7 44.5 47.7 -3.2 3 68 1977 2002 1952 1952 bottom-tenth 1978 8 46.9 50.3 -3.4 3 68 1977 2002,2017 1952 1952 bottom-tenth 9 48.4 51.2 -2.8 3 68 1977 2002 1952 1952 bottom-tenth 1970,1997 10 47.9 50.8 -2.9 2 69 1977 2002 1952 1952 bottom-tenth 1997 11 46.0 49.4 -3.4 2 69 1977 2013 1952 1952 bottom-tenth 12 43.9 47.2 -3.3 1 70 1952 2013 1952 1952 lowest 18 -99 46.0 -99 -99 -99 1979 2017 normal 24 -99 47.2 -99 -99 -99 2015 2013 normal 36 -99 47.2 -99 -99 -99 1963,1979 2013,2018 normal 48 -99 47.2 -99 -99 -99 1980 2002 normal 60 -99 47.2 -99 -99 -99 1963,1980 2003 normal