1991-2020 Degrees Fahrenheit 1 16.6 23.5 -6.9 22 63 1949 2006 1952 1953 bottom-third 2 24.4 23.4 1.0 51 33 1949 1958 1952 1953 normal 3 29.3 26.8 2.5 69 15 1979 2021 1953 1939 top-third 1975 4 34.7 31.7 3.0 78 5 1979 2000 1953 1954 top-tenth 5 39.9 37.2 2.7 77 6 1979 2022 1953 1954 top-tenth 6 44.7 42.6 2.1 77 6 1986 2021 1953 1954 top-tenth 1999 7 48.6 46.7 1.9 77 6 1979 2022 1953 1954 top-tenth 2012 8 50.0 48.7 1.3 74 9 1952,1979 2022 1953 1954 top-third 9 50.0 49.3 0.7 64 19 1979 2022 1953 1941 top-third 10 49.2 48.9 0.3 57 26 1952 2022 1952 1953 top-third 1988,2012 11 48.1 47.8 0.3 60 21 1952 2016 1953 1941 top-third 12 46.6 46.1 0.5 63 18 1952 2016 1953 1941 top-third 1975,1992 18 45.6 44.9 0.7 68 11 1952 2013,2022 1953 1941 top-third 2001 24 46.2 46.0 0.2 59 18 1950 2017 1953 1942 top-third 1993 36 44.4 46.0 -1.6 17 56 1952 2018 1953 1948 bottom-third 1997 48 44.2 46.0 -1.8 10 59 1952 2019 1953 1949 bottom-third 1946,1972 60 43.9 46.0 -2.1 3 62 1952,1953 2008,2009,2020 1953 1951 bottom-tenth 1951