1991-2020 Degrees Fahrenheit 1 25.7 33.3 -7.6 12 73 1965 2012 2002 2013 bottom-third 1956 2 17.2 27.0 -9.8 2 83 1965 2012 1965 2013 bottom-tenth 3 14.2 23.4 -9.2 2 83 1979 2012 1979 2013 bottom-tenth 4 13.8 23.0 -9.2 1 84 2014 2012 2014 2013 lowest 5 17.7 25.4 -7.7 3 82 1951 2012 1956 2013 bottom-tenth 6 22.9 29.4 -6.5 1 84 2014 2012 2014 2013 lowest 7 29.3 34.3 -5.0 6 79 1951,1978 2012 1978 2013 bottom-tenth 8 34.9 39.0 -4.1 7 78 1978 2012 1979 2013 bottom-tenth 1979 9 39.4 42.9 -3.5 11 74 1951 2012 1994 2013 bottom-third 1986 10 42.3 45.6 -3.3 11 74 1951 2012 1994 2013 bottom-third 11 43.8 46.9 -3.1 12 73 1951 2012 1994 2013 bottom-third 1986 12 43.6 46.9 -3.3 6 79 1951 2012 1994 2013 bottom-tenth 1946 18 38.6 41.0 -2.4 18 66 1951,1952 2017 1997 2013 bottom-third 1948 24 45.7 46.9 -1.2 40 44 1952 2017 1998 2013 normal 1958,1998 36 47.4 46.9 0.5 69 14 1952 2018 2011 2013 top-third 48 47.3 46.9 0.4 70 12 1953 2013,2019 2011 2013 top-third 60 47.2 46.9 0.3 69 12 1952 2020 2012 2013 top-third 1991,2009,2012