1991-2020 Degrees Fahrenheit 1 58.0 60.0 -2.0 26 52 1964 1997 1991 1993 bottom-third 2 57.3 58.8 -1.5 35 43 1964 1992 1991 1993 normal 1954 3 57.0 57.8 -0.8 47 31 1948 1992 1991 1993 normal 2009 4 55.5 56.8 -1.3 34 43 1948 1992 1991 1993 normal 1968,1972,1983,1991 5 54.8 55.7 -0.9 46 31 1949 2014,2015,2016 1991 1993 normal 1958,2001 6 54.1 55.0 -0.9 44 33 1949 2015 1991 1993 normal 1998,2009 7 54.5 55.2 -0.7 44 33 1949 2015 1991 1993 normal 8 55.7 56.2 -0.5 50 27 1949 2015 1991 1993 normal 1986,2002 9 56.5 57.2 -0.7 47 30 1949 2015 1991 1993 normal 1980,1981,2006 10 57.6 58.0 -0.4 51 26 1949 2015 1991 1993 normal 2011 11 58.3 58.6 -0.3 54 22 1949 2015 1991 1993 top-third 12 58.9 58.9 0.0 57 18 1949 2015 1991 1993 top-third 2003 18 57.7 57.6 0.1 57 17 1949,1950 2015,2016 1992 1993 top-third 24 59.3 58.8 0.5 63 10 1950 2016 1992 1993 top-third 36 59.3 58.8 0.5 64 7 1950 2016 1993 1994 top-tenth 2005 48 59.1 58.8 0.3 65 4 1951,1952,1955,1956 2018 1993 1994 top-tenth 2006,2015 60 58.8 58.7 0.1 58 10 1952,1953,1956 2018 1993 1988 top-third 1988,2000,2005