1991-2020 Degrees Fahrenheit 1 23.3 24.5 -1.2 42 34 1979 1995 1949 1950 normal 1969,1977 2 21.7 20.9 0.8 46 30 1984 1995 1949 1950 normal 3 22.2 20.0 2.2 56 18 1992 1995,2018 1950 1951 top-third 2017 4 24.4 22.6 1.8 56 18 1992 2018 1949 1950 top-third 5 29.2 26.9 2.3 63 11 1992 2018 1950 1951 top-third 6 33.2 31.8 1.4 58 16 1992 2018 1950 1951 top-third 1957 7 36.9 36.3 0.6 53 21 1992 2018 1950 1951 top-third 1986 8 40.1 40.0 0.1 47 27 1992 2018 1949 1950 normal 9 42.2 42.3 -0.1 43 31 1992 2018 1949 1950 normal 10 42.8 43.2 -0.4 41 33 1992 2018 1949 1950 normal 1954,2007 11 42.7 43.2 -0.5 40 34 1992 2018 1949 1950 normal 1956,1963,1990 12 41.7 42.5 -0.8 37 37 1992 2018 1949 1950 normal 18 38.7 38.9 -0.2 48 24 1993 2018 1950 1951 top-third 1955,2013 24 41.9 42.5 -0.6 45 27 1993 2018 1950 1951 normal 1956,1983,1987,2008 36 41.3 42.4 -1.1 33 37 1993,1994 2018 1951 1951 normal 1952,1955,1961,1964 48 -99 42.3 -99 -99 -99 1976 2019 normal 60 -99 42.2 -99 -99 -99 1977 2020 normal