1991-2020 Degrees Fahrenheit 1 30.5 31.4 -0.9 40 36 1989 2015 1966 1965 normal 2 32.8 36.3 -3.5 14 62 1989 2015 1963 1966 bottom-third 3 39.3 41.3 -2.0 20 56 1976 2015 1962 1966 bottom-third 1986,2019 4 44.8 46.7 -1.9 22 54 1976 2015 1963 1966 bottom-third 1963 5 49.5 51.4 -1.9 19 57 1976 2015 1964 1966 bottom-third 6 53.2 54.8 -1.6 21 55 1976 2015 1965 1966 bottom-third 1954,1955,1974,1985 7 55.1 56.4 -1.3 28 48 1958,1976 2015 1965 1966 normal 8 54.4 56.5 -2.1 10 65 1958 2015 1962 1966 bottom-third 1997 9 -99 55.5 -99 -99 -99 1958,1972 2015 normal 10 -99 53.5 -99 -99 -99 1972 2012 normal 11 -99 51.1 -99 -99 -99 1958,1972 2012 normal 12 -99 49.0 -99 -99 -99 1958 2012 normal 18 -99 50.9 -99 -99 -99 1963,1977 2012 normal 24 -99 49.0 -99 -99 -99 1963 2012 normal 36 -99 49.0 -99 -99 -99 1972 2012 normal 48 -99 49.0 -99 -99 -99 1963,1965 2013 normal 60 -99 48.9 -99 -99 -99 1962,1966,1972 2022 normal