1991-2020 Degrees Fahrenheit 1 65.3 67.8 -2.5 17 51 1969 2011 1981 1982 bottom-third 2 61.6 64.2 -2.6 20 47 1965 2000 1982 1980 bottom-third 2001 3 59.0 61.3 -2.3 20 47 1968 2000 1982 1981 bottom-third 1969 4 57.9 59.9 -2.0 18 49 1968 2000 1979 1982 bottom-third 5 58.8 60.6 -1.8 18 49 1977 2000,2017 1979 1982 bottom-third 6 61.5 63.0 -1.5 22 45 1977 2017 1981 1982 bottom-third 7 64.8 65.9 -1.1 24 43 1977 2017 1979 1982 normal 8 67.9 68.9 -1.0 25 42 1977 2017 1981 1982 normal 1954,1967,2021 9 70.3 71.1 -0.8 24 43 1977 2017 1982 1982 normal 1967,1982,1989,1997,2005,2019 10 71.9 72.8 -0.9 27 40 1977 2017 1982 1981 normal 1971,2005 11 72.6 73.6 -1.0 23 44 1977 1999 1982 1981 normal 1978,2015 12 72.7 73.7 -1.0 23 43 1977 2023 1982 1981 normal 1972,1985,1989 18 69.2 70.1 -0.9 23 42 1977 2023 1982 1981 normal 1993,2008,2011 24 72.5 73.7 -1.2 18 46 1977,1978 2000 1980 1982 bottom-third 1972,1985 36 72.8 73.7 -0.9 22 40 1979 2013 1982 1982 normal 1982,1987 48 72.8 73.6 -0.8 24 36 1978,1979 2002 1982 1957 normal 1986 60 72.6 73.6 -1.0 19 39 1977 2020 1982 1982 bottom-third 1982,1992