1991-2020 Degrees Fahrenheit 1 55.7 60.6 -4.9 3 76 1967 1992 1953 1952 bottom-tenth 2 55.3 59.7 -4.4 7 72 1967 2015 1952 1951 bottom-tenth 3 55.5 58.9 -3.4 13 66 1949 2015 1952 1947 bottom-third 4 55.9 58.5 -2.6 24 55 1949 2015 1952 1947 bottom-third 1960,1999 5 55.5 58.3 -2.8 18 61 1949 2015 1952 1947 bottom-third 1965,1972 6 55.7 58.8 -3.1 12 67 1949 2015 1952 1947 bottom-third 7 56.6 59.9 -3.3 10 69 1949 2015 1952 1951 bottom-third 1962 8 57.8 61.1 -3.3 10 69 1949 2015 1952 1947 bottom-third 9 58.8 62.1 -3.3 9 70 1949 2016 1952 1947 bottom-third 1946,1954 10 59.3 62.8 -3.5 6 72 1949 2015 1952 1951 bottom-tenth 1951 11 59.5 63.1 -3.6 5 73 1949 2015 1952 1951 bottom-tenth 1948,1951 12 59.6 63.1 -3.5 6 72 1949 2015 1952 1948 bottom-tenth 18 57.9 61.6 -3.7 4 74 1949 2015 1951 1952 bottom-tenth 1956 24 59.5 63.0 -3.5 5 72 1950 2016 1952 1948 bottom-tenth 1956 36 59.5 63.0 -3.5 5 71 1951 2016 1952 1948 bottom-tenth 48 59.4 62.9 -3.5 4 71 1952 2018 1952 1949 bottom-tenth 60 59.1 62.9 -3.8 1 73 1953 2018 1953 1952 lowest