1991-2020 Degrees Fahrenheit 1 32.9 31.8 1.1 66 23 2015 2018 2008 2004 top-third 2 28.9 30.9 -2.0 39 50 2015 2002 2005 2008 normal 1993,2005 3 31.2 32.6 -1.4 50 38 1948 2002 2005 2008 normal 1988 4 34.2 35.6 -1.4 49 39 1948 2002,2012 2004 2008 normal 1950,1972 5 38.0 39.4 -1.4 49 39 1977 2012 2004 2008 normal 1967,1985,1988 6 42.6 43.8 -1.2 52 36 1977 2012 2004 2008 normal 1950 7 46.5 47.9 -1.4 49 39 1977 2012 2003 2008 normal 1985 8 50.1 51.2 -1.1 52 36 1977 2012 2005 2008 normal 1951,1976 9 52.3 53.1 -0.8 57 31 1941,1963 2012 2005 2008 normal 10 52.9 53.6 -0.7 58 30 1941,1963,1968 2012,2023 2005 2008 normal 1972 11 52.5 53.1 -0.6 58 30 1941 2012 2005 2008 normal 2010 12 51.3 51.9 -0.6 61 27 1941 2023 2005 2008 top-third 1998 18 49.1 49.2 -0.1 67 20 1941 2017 2006 2008 top-third 1984 24 51.8 51.8 0.0 68 19 1941 2023 2006 2008 top-third 2016 36 52.0 51.8 0.2 72 14 1941,1942 2023 2007 2008 top-third 2011 48 51.9 51.8 0.1 70 15 1941 2023 2008 2008 top-third 2000,2003,2008 60 51.8 51.7 0.1 68 16 1944 2023 2008 2003 top-third 2010