1991-2020 Degrees Fahrenheit 1 57.4 59.7 -2.3 39 46 1960 2012 1998 1997 normal 2 57.7 56.1 1.6 74 11 1960 2017 1998 1992 top-third 1992 3 56.0 53.6 2.4 77 8 1978 2017 1998 1990 top-tenth 2016 4 54.5 52.8 1.7 76 9 1978 2017 1998 1976 top-third 5 55.5 53.7 1.8 79 6 1978 2017 1998 1999 top-tenth 6 57.8 56.1 1.7 77 8 1978 2017 1998 1999 top-tenth 7 61.4 59.3 2.1 81 4 1977 2017 1998 1999 top-tenth 2023 8 64.4 62.5 1.9 81 4 1977 2017 1998 1999 top-tenth 9 67.2 65.0 2.2 81 4 1977 2017 1998 1999 top-tenth 10 69.1 66.6 2.5 80 4 1977 2017 1998 1999 top-tenth 11 69.9 67.4 2.5 80 4 1977 2017 1998 1999 top-tenth 12 69.5 67.3 2.2 80 4 1977 2017 1998 1999 top-tenth 18 64.7 63.5 1.2 77 7 1941 2017 1998 1999 top-tenth 2006,2016 24 67.6 67.3 0.3 72 11 1978 2017 1998 1999 top-third 2008 36 67.2 67.2 0.0 65 17 1979 2018 1998 1957 top-third 1957,2005,2016 48 67.0 67.2 -0.2 59 22 1980 2019 1998 1957 top-third 60 67.0 67.2 -0.2 59 21 1962 2020 1998 1999 top-third 2004,2011