1991-2020 Degrees Fahrenheit 1 22.0 19.8 2.2 52 23 1983 2020 1993 1991 top-third 2019 2 25.5 24.8 0.7 49 26 1955 1999 1993 1991 normal 3 32.3 31.1 1.2 55 20 1951 1999 1993 1987 top-third 4 39.4 37.8 1.6 59 16 1951 2021 1993 1987 top-third 5 45.0 43.8 1.2 62 13 1951 2021 1993 1987 top-third 6 48.6 48.0 0.6 56 19 1951 2021 1993 1988 top-third 7 50.5 50.0 0.5 54 20 1951 2021 1993 1991 top-third 1954,1962,1979 8 51.2 50.3 0.9 58 16 1951 2021 1993 1991 top-third 1991,2018 9 50.1 49.3 0.8 56 18 1951 1988 1993 1991 top-third 2011 10 48.3 47.4 0.9 58 16 1951 2021 1993 1991 top-third 11 44.5 44.8 -0.3 47 27 1951 1987 1993 1992 normal 1953,1992 12 41.2 42.4 -1.2 32 42 1950 1987 1993 1992 normal 1954,1958,1995 18 42.2 44.3 -2.1 20 53 1951 2012,2021 1993 1992 bottom-third 2010,2019 24 40.2 42.4 -2.2 15 57 1951 1988 1983 1993 bottom-third 1955,1967,1983 36 41.2 42.3 -1.1 30 40 1951 1988 1984 1993 normal 48 41.8 42.4 -0.6 42 26 1952 1990 1986 1993 normal 1983,1986 60 42.2 42.4 -0.2 44 22 1953 1991 1993 1993 top-third 1993,1999