1991-2020 Degrees Fahrenheit 1 45.9 51.6 -5.7 6 73 1949 2019 1955 1956 bottom-tenth 2 47.3 51.5 -4.2 9 70 1949 2015 1955 1956 bottom-third 1962 3 49.8 53.2 -3.4 11 68 1949 2015 1955 1956 bottom-third 1985 4 51.9 55.6 -3.7 4 75 1949 2015 1955 1956 bottom-tenth 1955 5 54.3 57.6 -3.3 6 73 1949 2015 1955 1956 bottom-tenth 1950,1963 6 55.7 58.8 -3.1 6 73 1949 2015 1955 1956 bottom-tenth 7 56.6 59.6 -3.0 7 71 1949 2015 1955 1956 bottom-tenth 1952 8 57.2 60.0 -2.8 8 69 1949 2015 1955 1956 bottom-tenth 1972 9 57.3 60.0 -2.7 9 68 1949 2015 1955 1956 bottom-third 10 57.0 59.7 -2.7 11 66 1949 2015 1956 1954 bottom-third 11 56.6 59.4 -2.8 11 66 1949 2015 1956 1954 bottom-third 12 55.9 58.9 -3.0 6 70 1949 2015 1956 1956 bottom-tenth 1955,1956,1966,1972 18 56.0 58.8 -2.8 6 70 1950 2016,2021 1956 1955 bottom-tenth 24 55.9 58.8 -2.9 2 71 1950 2016 1956 1956 bottom-tenth 1956 36 55.9 58.8 -2.9 1 70 1951,1957 2017 1951 1956 lowest 1951 48 56.0 58.8 -2.8 2 67 1952 2018 1952 1956 bottom-tenth 60 56.1 58.7 -2.6 2 65 1953 2018 1956 1956 bottom-tenth 1956