1991-2020 Degrees Fahrenheit 1 40.2 32.1 8.1 78 5 1943 2012 1945 1946 top-tenth 2 28.5 26.3 2.2 70 13 2014 2012 1945 1946 top-third 3 24.3 23.1 1.2 65 17 2014 2012 1945 1946 top-third 1981 4 21.9 23.0 -1.1 54 28 2014 2012 1945 1944 normal 1953,1958,1968 5 23.7 25.3 -1.6 45 35 2014 2012 1944 1945 normal 1975 6 27.5 29.2 -1.7 36 44 2014 2012 1943 1945 normal 1947,1953,1968 7 31.8 33.8 -2.0 35 45 1977,2014 2016 1944 1945 normal 1947,1949 8 36.4 38.2 -1.8 34 46 1943,1951,1965,1977,2014 2016 1944 1945 normal 1944,1966,2003 9 39.9 41.9 -2.0 27 53 1951 2012 1943 1945 normal 10 42.1 44.4 -2.3 20 60 1951 2012 1943 1945 bottom-third 1955 11 42.9 45.6 -2.7 14 66 1943,1951 2012 1943 1945 bottom-third 1955,1972 12 43.0 45.6 -2.6 14 66 1951 2016 1943 1945 bottom-third 1972,1996 18 38.0 40.1 -2.1 20 57 1952 2017 1944 1945 bottom-third 1973,1977 24 43.8 45.6 -1.8 25 52 1952 2017 1944 1945 bottom-third 1957 36 43.9 45.6 -1.7 24 51 1953 2000 1945 1946 bottom-third 1947,1962,1966,1974,1982,1996 48 43.5 45.6 -2.1 10 63 1980 2002 1946 1946 bottom-third 1954,1959,1962,1966,1982,1996 60 -99 45.6 -99 -99 -99 1969,1971,1972 2002 normal