1991-2020 Degrees Fahrenheit 1 26.3 35.5 -9.2 2 59 1965 2012 1965 2013 bottom-tenth 2 21.9 30.9 -9.0 2 59 1978 2012 1978 2013 bottom-tenth 3 20.6 28.8 -8.2 2 59 1978 2012 1978 2013 bottom-tenth 4 21.9 29.1 -7.2 2 59 1978 2012 1978 2013 bottom-tenth 5 25.0 31.2 -6.2 1 59 2014 2012 2014 2013 lowest 6 29.6 34.6 -5.0 4 56 1977 2012 1978 2013 bottom-tenth 7 34.4 38.6 -4.2 5 55 1977 2012 1994 2013 bottom-tenth 8 38.8 42.6 -3.8 3 57 1977 2012 1978 2013 bottom-tenth 9 42.6 46.0 -3.4 4 56 1977 2012 1979 2013 bottom-tenth 1965,1970 10 45.1 48.2 -3.1 5 55 1970,1977,1978 2012 1994 2013 bottom-tenth 1994 11 46.7 49.2 -2.5 9 51 1977 2012 1994 2013 bottom-third 2015 12 46.5 49.0 -2.5 5 55 1970,1977 2012 1994 2013 bottom-tenth 18 42.5 44.2 -1.7 14 45 1979 2017 1997 2013 bottom-third 24 48.3 49.0 -0.7 31 28 1978 2017 2010 2013 normal 1991 36 49.6 49.0 0.6 45 13 1979 2018 2011 2013 top-third 48 49.6 49.0 0.6 49 8 1970,1980 2019 2012 2013 top-third 2012,2022 60 49.4 48.9 0.5 46 10 1970,1971,1981 2020 2011 2013 top-third 2008