1991-2020 Degrees Fahrenheit 1 42.8 41.9 0.9 46 29 1950 1987 1990 1991 normal 2 39.6 36.3 3.3 61 14 1950 2012 1991 1988 top-third 3 36.6 30.8 5.8 70 5 2019 2012 1991 1987 top-tenth 4 34.5 27.3 7.2 74 1 1950 1992 1991 1992 highest 5 33.2 25.9 7.3 73 1 1950 1992 1991 1992 highest 6 32.1 26.7 5.4 71 3 1979 2000 1991 1992 top-tenth 7 33.4 29.2 4.2 69 5 1950 2000,2012 1991 1981 top-tenth 8 36.4 32.9 3.5 68 6 1950 2012 1991 1981 top-tenth 9 40.5 36.9 3.6 69 5 1965 2012 1991 1992 top-tenth 10 43.5 40.2 3.3 69 5 1952 1999,2012 1991 1992 top-tenth 11 45.5 42.3 3.2 70 3 1952 2012 1991 1992 top-tenth 1999 12 46.3 43.2 3.1 70 3 1951,1952 1981 1991 1981 top-tenth 18 40.2 37.7 2.5 68 4 1951 2000 1991 1988 top-tenth 1981,2016 24 45.3 43.2 2.1 68 3 1952 2000 1991 1992 top-tenth 36 45.1 43.2 1.9 67 2 1952 2000 1991 1992 top-tenth 48 44.9 43.2 1.7 65 2 1953 2001 1991 1992 top-tenth 60 45.0 43.3 1.7 64 1 1954 1992 1991 1992 highest