1991-2020 Degrees Fahrenheit 1 28.8 19.8 9.0 74 1 1983 2020 2019 2020 highest 2 32.4 24.9 7.5 73 2 1955 1999 2019 1999 top-tenth 3 34.1 31.1 3.0 67 8 1951 1999 2019 2015 top-third 1962,1974,1997 4 40.2 37.8 2.4 65 10 1951 2021 2019 2015 top-third 2001,2004 5 46.3 43.8 2.5 68 7 1951 2021 2019 2015 top-tenth 2011 6 50.3 48.0 2.3 71 4 1951 2021 2019 2015 top-tenth 2001 7 52.5 50.1 2.4 70 4 1951 2021 2019 2015 top-tenth 8 52.5 50.4 2.1 69 5 1951 2021 2019 2015 top-tenth 9 51.0 49.4 1.6 65 9 1951 1988 2019 2015 top-third 2012 10 49.2 47.4 1.8 66 8 1951 2021 2019 2015 top-third 2001 11 46.9 44.8 2.1 66 8 1951 1987 2019 2015 top-third 1998 12 44.5 42.4 2.1 66 8 1950 1987 2019 2015 top-third 18 45.3 44.3 1.0 61 12 1951 2012,2021 2019 2016 top-third 1991 24 42.1 42.4 -0.3 44 28 1951 1988 2019 2018 normal 2003 36 41.9 42.4 -0.5 45 25 1951 1988 2019 2018 normal 48 42.1 42.4 -0.3 45 23 1952 1990 2019 2019 normal 2019 60 42.6 42.5 0.1 50 16 1953 1991 2012 2019 top-third 2005,2009,2022