1991-2020 Degrees Fahrenheit 1 31.8 39.9 -8.1 10 75 1989 2015 1960 1961 bottom-third 2 37.6 44.4 -6.8 5 80 1989 2015 1955 1961 bottom-tenth 3 44.3 49.4 -5.1 4 81 1976,1980 2015 1945 1961 bottom-tenth 1945 4 49.5 54.7 -5.2 2 82 1976 2015 1962 1961 bottom-tenth 5 54.2 59.3 -5.1 1 83 1962 2015 1962 1961 lowest 6 57.5 62.5 -5.0 1 83 1962 2015 1962 1961 lowest 7 59.7 64.1 -4.4 1 83 1962 2015 1962 1961 lowest 8 60.1 64.0 -3.9 1 83 1958,1962 2015 1958 1961 lowest 1958 9 59.2 62.8 -3.6 3 81 1940 2015 1950 1961 bottom-tenth 1950 10 57.4 60.8 -3.4 4 80 1940 2016 1958 1961 bottom-tenth 1958 11 55.1 58.6 -3.5 6 78 1940 2016 1958 1961 bottom-tenth 1978 12 53.1 56.6 -3.5 4 80 1940 2020 1958 1961 bottom-tenth 18 56.1 58.5 -2.4 18 65 1963 2016 1958 1961 bottom-third 1979 24 53.8 56.5 -2.7 10 73 1941 2021 1948 1961 bottom-third 1945,1967 36 53.9 56.5 -2.6 10 72 1942 2022 1945 1961 bottom-third 1943,1967,1978 48 54.3 56.5 -2.2 24 57 1943 2021,2022 1961 1960 bottom-third 1958 60 54.0 56.4 -2.4 9 71 1944 2020 1948 1961 bottom-third 1946,1964,1965,1966,1967,1968,1971,1980