1991-2020 Degrees Fahrenheit 1 63.0 65.8 -2.8 15 64 1964 1981 1950 1949 bottom-third 2 60.9 64.4 -3.5 5 74 1964 2014 1950 1949 bottom-tenth 3 59.5 63.2 -3.7 6 73 1967 2014 1950 1949 bottom-tenth 4 58.5 62.0 -3.5 10 69 1964 2014 1950 1949 bottom-third 1999 5 57.2 61.1 -3.9 3 76 1950 2014 1950 1949 bottom-tenth 1945,1964 6 56.4 60.5 -4.1 5 74 1950 2014 1950 1948 bottom-tenth 1948 7 56.5 60.0 -3.5 8 71 1950 2014 1950 1947 bottom-tenth 8 57.0 60.3 -3.3 10 69 1949 2014 1950 1947 bottom-third 9 57.7 60.9 -3.2 9 70 1949 2014 1950 1947 bottom-third 1953,1962 10 58.4 61.8 -3.4 8 71 1949 2014,2016 1950 1947 bottom-tenth 11 58.9 62.5 -3.6 6 73 1949 2016 1950 1947 bottom-tenth 1955 12 59.6 63.1 -3.5 6 72 1949 2016 1950 1947 bottom-tenth 18 58.1 62.2 -4.1 3 75 1950 2015 1950 1948 bottom-tenth 24 59.2 63.0 -3.8 3 74 1950 2016 1950 1948 bottom-tenth 36 58.9 63.0 -4.1 2 74 1950 2016 1950 1949 bottom-tenth 48 59.0 62.9 -3.9 1 74 1951,1952 2017,2018 1951 1950 lowest 1952 60 59.3 62.9 -3.6 3 71 1952,1953 2018 1951 1950 bottom-tenth