1991-2020 Degrees Fahrenheit 1 55.8 55.2 0.6 47 16 1966 2017 2007 2008 top-third 2 49.7 49.8 -0.1 36 27 1984 2010 2007 2008 normal 1963 3 45.8 45.4 0.4 40 23 1978 2017,2023 2007 2008 normal 4 41.8 42.6 -0.8 34 29 1978 2023 2007 2008 normal 1989 5 41.1 41.7 -0.6 35 28 1978 2023 2005 2008 normal 2005 6 41.6 42.4 -0.8 32 28 1970 2023 2003 2008 normal 7 43.5 44.5 -1.0 28 32 1970 2017 2003 2008 normal 2011 8 46.8 47.5 -0.7 28 32 1970 2017 2003 2008 normal 1997 9 49.8 50.6 -0.8 30 30 1970 2017 2003 2008 normal 1997 10 52.5 53.3 -0.8 30 30 1970,1977 2017 2003 2008 normal 11 54.5 55.1 -0.6 33 27 1970,1977 2017 2004 2008 normal 12 55.0 55.8 -0.8 32 28 1977 2017 2004 2008 normal 18 51.0 51.3 -0.3 37 21 1970 2017 2004 2008 normal 1998 24 56.1 55.8 0.3 44 14 1978 2017 2005 2008 top-third 36 55.9 55.7 0.2 42 14 1970 2023 2006 2008 top-third 1992,2002,2006 48 56.2 55.7 0.5 45 9 1970 2023 2007 2008 top-third 2011,2014 60 56.1 55.7 0.4 42 10 1970 2023 2008 2008 top-third 2008,2011