1991-2020 Degrees Fahrenheit 1 43.1 41.6 1.5 48 29 1960 2012 1965 1963 normal 2003 2 36.9 37.1 -0.2 42 35 1978 2012 1965 1961 normal 3 32.4 34.6 -2.2 24 53 1978 2012 1965 1964 bottom-third 4 33.8 34.6 -0.8 38 38 1978 2012 1965 1957 normal 5 36.0 36.4 -0.4 41 35 1978 2012 1965 1957 normal 2004,2005,2008,2018 6 39.2 39.6 -0.4 40 36 1977 2012 1965 1957 normal 2005 7 43.6 43.5 0.1 45 31 1977 2017 1965 1957 normal 1990 8 47.2 47.3 -0.1 44 32 1977 2017 1965 1961 normal 1961 9 50.1 50.4 -0.3 39 37 1977 2017 1965 1957 normal 1988 10 52.1 52.5 -0.4 34 42 1977 2017 1965 1960 normal 1952,1956,1960,1967,1990 11 53.7 53.5 0.2 51 25 1977 2017 1965 1954 top-third 1972,1988 12 53.6 53.5 0.1 50 26 1977 2012 1965 1956 normal 1955,1956,1986,1988 18 48.5 48.8 -0.3 41 34 1978 2017 1965 1956 normal 1972 24 53.3 53.4 -0.1 46 29 1978 2017 1965 1957 normal 1989,1993,2002,2016 36 52.9 53.4 -0.5 34 40 1979 2018 1965 1958 normal 48 52.4 53.4 -1.0 17 56 1980 2019,2020 1965 1961 bottom-third 60 52.2 53.3 -1.1 8 64 1981 2020 1965 1964 bottom-third 1964,1970,1971,1978,1983,1984