1991-2020 Degrees Fahrenheit 1 35.5 38.2 -2.7 26 51 1978 1976 1980 1981 normal 2 32.4 36.6 -4.2 17 60 1978 2017 1980 1981 bottom-third 3 33.2 37.4 -4.2 12 65 1977 2017 1979 1981 bottom-third 4 36.3 39.6 -3.3 13 63 1977 2017 1979 1981 bottom-third 2003 5 39.9 43.1 -3.2 11 65 1977 2017 1981 1981 bottom-third 1981 6 44.4 47.3 -2.9 9 66 1977 2017 1978 1981 bottom-third 1958 7 48.5 51.2 -2.7 8 67 1977 2017 1978 1981 bottom-third 8 52.0 54.3 -2.3 10 65 1977 2017 1978 1981 bottom-third 1958 9 54.4 56.3 -1.9 12 63 1977 2017 1980 1981 bottom-third 2014 10 55.0 57.1 -2.1 9 66 1977 2017 1978 1981 bottom-third 11 55.4 57.1 -1.7 12 63 1977 2017 1980 1981 bottom-third 1959,2001 12 54.3 56.2 -1.9 9 66 1977 2017 1977 1981 bottom-third 1951,1966,2014 18 51.2 53.2 -2.0 10 64 1978 2017 1979 1981 bottom-third 1963 24 54.3 56.1 -1.8 9 65 1978 2017 1978 1981 bottom-third 1970 36 54.5 56.1 -1.6 10 63 1979 2018 1979 1981 bottom-third 48 54.5 56.1 -1.6 10 62 1964,1980 2020 1981 1981 bottom-third 1963,1981 60 54.5 56.1 -1.6 11 60 1981 2020 1981 1978 bottom-third