1991-2020 Degrees Fahrenheit 1 29.8 27.9 1.9 58 18 2014 2012 1985 1979 top-third 2 21.7 23.5 -1.8 34 41 2015 2012 1982 1985 normal 2011 3 19.7 21.2 -1.5 41 33 2015 2012 1985 1983 normal 1988 4 19.1 21.8 -2.7 28 45 1971 2016 1984 1985 normal 5 22.0 24.3 -2.3 32 41 1959,1971 2012 1984 1985 normal 1966 6 25.9 27.8 -1.9 31 42 1959 2012 1984 1985 normal 1952,1975,1989 7 30.1 32.1 -2.0 33 40 1959 2012 1984 1985 normal 1952,2004 8 34.0 36.2 -2.2 30 43 1959 2012 1984 1985 normal 1952 9 37.4 39.6 -2.2 29 43 1959 2012 1984 1985 normal 1988 10 39.4 41.8 -2.4 22 49 1959 2012 1982 1985 bottom-third 1973,2003 11 40.6 42.9 -2.3 23 47 1959 2012 1984 1985 bottom-third 1973 12 40.5 42.7 -2.2 23 47 1959 2012 1984 1985 bottom-third 1969,2003 18 36.1 37.9 -1.8 31 36 1971,1982 2013 1985 1984 normal 24 41.0 42.9 -1.9 25 39 1968 2013 1985 1984 normal 1962,1980,1981,1988 36 40.8 43.0 -2.2 22 37 1965,1968,1970 2018,2023 1982 1985 normal 1958,1988 48 41.4 43.0 -1.6 32 23 1968,1970,1971 2013 1985 1954 normal 60 41.0 43.1 -2.1 26 25 1971 2013 1985 1983 normal 1957,1958,1983