1991-2020 Degrees Fahrenheit 1 16.4 20.3 -3.9 37 46 2014 1998 1970 1969 normal 2 11.6 18.5 -6.9 10 72 1963 2002 1970 1970 bottom-third 1970 3 14.3 19.7 -5.4 17 65 2014 2002 1965 1970 bottom-third 1956 4 19.0 23.5 -4.5 19 61 1977 2002 1965 1970 bottom-third 5 25.2 28.4 -3.2 21 59 1977 2002 1970 1969 bottom-third 6 31.1 33.9 -2.8 22 58 1977 2002 1970 1969 bottom-third 2009 7 36.5 38.9 -2.4 23 57 1977 2002 1970 1969 bottom-third 1955,1973 8 41.0 42.9 -1.9 29 51 1977 2002 1970 1969 normal 9 43.9 45.6 -1.7 28 52 1977 2002 1970 1969 normal 1947,1955,1956 10 45.1 46.8 -1.7 32 48 1977 2002 1970 1964 normal 1996 11 45.2 46.7 -1.5 34 46 1951 2002 1970 1964 normal 12 43.6 45.4 -1.8 30 50 1951 2002 1970 1969 normal 1961 18 39.1 41.6 -2.5 17 60 1952 2017 1970 1970 bottom-third 1970,1973 24 43.1 45.4 -2.3 12 65 1952 2017 1968 1970 bottom-third 1967 36 43.5 45.4 -1.9 19 56 1953 2013,2018 1970 1966 bottom-third 1947,1964,1965,1978 48 43.2 45.4 -2.2 7 66 1968 2002 1970 1969 bottom-tenth 1969,1979 60 43.2 45.4 -2.2 5 66 1955,1969,1970,1972 2002 1970 1968 bottom-tenth 1963,1966,1973,1980,1981