1991-2020 Degrees Fahrenheit 1 39.2 42.9 -3.7 19 57 1970 2002 1955 1954 bottom-third 2 35.4 39.1 -3.7 21 55 1964 2017 1955 1954 bottom-third 1979 3 30.1 34.2 -4.1 15 61 1984 2017 1955 1954 bottom-third 4 28.1 30.0 -1.9 34 42 1984 2015 1955 1954 normal 5 27.3 27.6 -0.3 46 28 1984 2018 1955 1954 normal 2004 6 27.6 28.0 -0.4 43 31 1973 2018 1955 1954 normal 1982,1997,2007 7 29.9 30.3 -0.4 44 30 1984 2018 1955 1954 normal 1982,1989,2007 8 33.0 33.5 -0.5 43 31 1984 2018 1955 1954 normal 1950,2019 9 36.4 36.8 -0.4 49 25 1973,1992 2018 1955 1956 normal 1990,2019 10 39.1 39.7 -0.6 45 29 1973 2018 1955 1954 normal 2007 11 40.8 41.6 -0.8 41 33 1984 2018 1955 1954 normal 12 41.4 42.5 -1.1 38 36 1984 2018 1955 1954 normal 1950,1963 18 36.1 37.6 -1.5 27 45 1993 2018 1954 1955 normal 1963,1964,1998 24 41.2 42.5 -1.3 34 38 1993 2018 1954 1955 normal 1951 36 41.3 42.4 -1.1 40 30 1975 2018 1955 1956 normal 1959 48 41.1 42.2 -1.1 40 28 1976 2019 1955 1956 normal 1958,1988 60 40.8 42.1 -1.3 25 41 1977 2020 1955 1954 normal 1954,1970,1984,1991