1991-2020 Degrees Fahrenheit 1 60.5 66.0 -5.5 16 71 1973 2004 1935 1934 bottom-third 2 59.3 62.8 -3.5 22 64 1964 2015 1938 1935 bottom-third 3 58.1 60.7 -2.6 26 59 1949 2015 1938 1935 bottom-third 1974 4 58.0 59.4 -1.4 41 44 1949 2015 1935 1934 normal 2001 5 58.8 60.5 -1.7 31 53 1949 2015,2018 1935 1934 normal 1950,1961,1994 6 -99 63.2 -99 -99 -99 1949 2018 normal 7 -99 66.9 -99 -99 -99 1973 2018 normal 8 -99 70.3 -99 -99 -99 1942,1973 2018 normal 9 -99 73.0 -99 -99 -99 1942 2018,2021 normal 10 -99 74.8 -99 -99 -99 1942 2018 normal 11 -99 75.4 -99 -99 -99 1942 2021 normal 12 -99 75.2 -99 -99 -99 1942 2018,2021 normal 18 -99 71.2 -99 -99 -99 1942 2018 normal 24 -99 75.2 -99 -99 -99 1943,1966 2022 normal 36 -99 75.2 -99 -99 -99 1944 2018 normal 48 -99 75.2 -99 -99 -99 1975,1976 2018 normal 60 -99 75.1 -99 -99 -99 1976,1977 2018 normal