1991-2020 Degrees Fahrenheit 1 40.0 41.6 -1.6 29 48 1960 2012 1951 1949 normal 2 37.5 37.1 0.4 48 29 1978 2012 1951 1949 normal 1977 3 36.6 34.6 2.0 60 17 1978 2012 1951 1949 top-third 4 35.5 34.6 0.9 51 25 1978 2012 1951 1950 top-third 5 35.7 36.4 -0.7 33 43 1978 2012 1951 1950 normal 6 39.3 39.6 -0.3 44 32 1977 2012 1951 1950 normal 1985,1997,2019 7 43.0 43.5 -0.5 38 38 1977 2017 1951 1950 normal 1997 8 46.7 47.3 -0.6 31 45 1977 2017 1951 1950 normal 1956,1960,1985,1988,2005,2013 9 49.9 50.4 -0.5 33 43 1977 2017 1951 1950 normal 1960,1981 10 52.1 52.5 -0.4 34 42 1977 2017 1951 1950 normal 1956,1960,1966,1967,1990 11 53.2 53.5 -0.3 36 40 1977 2017 1951 1950 normal 1955,1973,1986 12 52.9 53.5 -0.6 31 45 1977 2012 1951 1950 normal 1998,2009 18 47.7 48.8 -1.1 21 54 1978 2017 1951 1951 bottom-third 1951,1981,1993,1995 24 51.9 53.4 -1.5 10 65 1978 2017 1952 1951 bottom-third 1969,1970,1980,1982 36 52.8 53.4 -0.6 32 42 1979 2018 1952 1951 normal 2016 48 53.2 53.4 -0.2 45 28 1980 2019,2020 1952 1952 normal 1958,1975,1991,1993,2005,2010 60 -99 53.3 -99 -99 -99 1981 2020 normal