1991-2020 Degrees Fahrenheit 1 45.7 51.8 -6.1 4 75 1949 2019 1950 1954 bottom-tenth 2 47.1 51.9 -4.8 5 74 1949 2015 1950 1954 bottom-tenth 3 49.4 53.6 -4.2 3 76 1949 2015 1949 1954 bottom-tenth 1947 4 52.2 56.0 -3.8 4 75 1949 2015 1950 1954 bottom-tenth 1950,1957 5 54.3 57.9 -3.6 2 77 1949 2015 1949 1954 bottom-tenth 1947 6 55.6 59.2 -3.6 3 76 1949 2015 1949 1954 bottom-tenth 7 56.7 60.0 -3.3 4 74 1949 2015 1950 1954 bottom-tenth 8 57.1 60.3 -3.2 3 74 1949 2015 1950 1954 bottom-tenth 1950 9 57.2 60.3 -3.1 4 73 1949 2015 1950 1954 bottom-tenth 10 57.2 60.1 -2.9 8 69 1949 2015 1952 1954 bottom-tenth 1963,1976 11 56.6 59.7 -3.1 3 74 1949 2015 1952 1954 bottom-tenth 1950,1952,1963 12 56.2 59.2 -3.0 5 71 1949 2015 1952 1954 bottom-tenth 1952,1956,1957,1966,1972 18 56.7 59.2 -2.5 10 66 1950 2016,2021 1953 1954 bottom-third 1953,1964 24 56.4 59.2 -2.8 4 69 1950 2016 1950 1954 bottom-tenth 36 56.6 59.1 -2.5 5 66 1951,1957 2017 1954 1954 bottom-tenth 1954 48 56.5 59.1 -2.6 3 66 1952 2018 1952 1954 bottom-tenth 1956 60 56.7 59.1 -2.4 5 62 1953 2018 1954 1955 bottom-tenth 1958,1966,1967