1991-2020 Degrees Fahrenheit 1 61.3 65.8 -4.5 2 77 1964 1981 1950 1949 bottom-tenth 2 59.8 64.4 -4.6 2 77 1964 2014 1950 1949 bottom-tenth 3 59.3 63.2 -3.9 4 75 1967 2014 1950 1949 bottom-tenth 1975 4 58.0 62.0 -4.0 4 75 1964 2014 1945 1949 bottom-tenth 1967,1975 5 56.8 61.1 -4.3 1 78 1950 2014 1950 1949 lowest 6 55.2 60.5 -5.3 1 78 1950 2014 1950 1949 lowest 7 54.7 60.0 -5.3 1 78 1950 2014 1950 1949 lowest 8 55.6 60.3 -4.7 2 77 1949 2014 1949 1948 bottom-tenth 9 56.2 60.9 -4.7 2 77 1949 2014 1949 1948 bottom-tenth 10 57.2 61.8 -4.6 2 77 1949 2014,2016 1949 1948 bottom-tenth 11 58.1 62.5 -4.4 2 77 1949 2016 1949 1948 bottom-tenth 12 58.7 63.1 -4.4 2 76 1949 2016 1949 1948 bottom-tenth 18 57.6 62.2 -4.6 1 77 1950 2015 1950 1949 lowest 24 58.5 63.0 -4.5 1 76 1950 2016 1950 1949 lowest 36 58.8 63.0 -4.2 1 75 1950 2016 1950 1949 lowest 48 59.2 62.9 -3.7 3 72 1951,1952 2017,2018 1950 1949 bottom-tenth 60 59.4 62.9 -3.5 4 70 1952,1953 2018 1950 1950 bottom-tenth