1991-2020 Degrees Fahrenheit 1 43.9 39.0 4.9 94 7 1960 2012 1999 1946 top-tenth 2 37.4 34.9 2.5 92 9 1934 2012 1999 1998 top-tenth 1991 3 34.0 32.7 1.3 85 14 1934 2012 1999 1998 top-third 4 34.1 32.9 1.2 85 14 1978 2012 1997 1999 top-third 1983 5 36.5 34.8 1.7 88 9 1934 2012 1999 1998 top-tenth 1991 6 38.8 37.9 0.9 81 15 1934 2012 1997 1999 top-third 1983 7 42.5 41.7 0.8 82 14 1934 2012 1997 1999 top-third 8 46.2 45.5 0.7 81 15 1934 2012 1997 1999 top-third 9 49.7 48.6 1.1 86 10 1934 2012 1999 1932 top-tenth 10 51.7 50.7 1.0 86 10 1934,1941 2012 1999 1932 top-tenth 11 52.4 51.5 0.9 84 12 1941 2012 1999 1999 top-third 1999,2008 12 52.1 51.4 0.7 85 11 1941 2012 1998 1999 top-third 1932 18 47.7 46.9 0.8 81 11 1941 2017 1998 1999 top-third 24 52.2 51.4 0.8 83 9 1926 2017 1999 2000 top-tenth 36 51.9 51.3 0.6 77 11 1941 2018,2022 1999 2000 top-third 48 51.5 51.3 0.2 71 14 1941 2019,2022 1999 2000 top-third 2007,2016 60 51.0 51.3 -0.3 62 20 1944 2020 1999 1999 top-third 1999,2001