1991-2020 Degrees Fahrenheit 1 55.0 55.5 -0.5 34 33 1979 1952 1992 1990 normal 2 56.7 55.7 1.0 49 18 1984 2022 1992 1989 top-third 3 58.1 58.3 -0.2 31 36 1977 2022 1992 1991 normal 1953 4 62.8 62.4 0.4 45 22 1977 2022 1992 1989 top-third 2008,2021,2023 5 67.1 66.6 0.5 47 20 1977 2022 1992 1989 top-third 2011 6 70.3 70.5 -0.2 38 29 1977 2022 1992 1989 normal 1965,1981,1994,1996,2007,2021 7 72.7 73.2 -0.5 29 38 1977 1952 1992 1989 normal 1997 8 74.3 75.0 -0.7 23 44 1977 1952 1992 1989 normal 1985,2004,2005,2009 9 74.6 75.8 -1.2 13 54 1977 1952 1988 1992 bottom-third 1987,2014 10 74.4 75.7 -1.3 10 56 1977 2012,2023 1988 1992 bottom-third 1970,1975,2014 11 73.7 75.0 -1.3 11 55 1977 2012 1991 1992 bottom-third 1972,1991,1998 12 72.7 73.8 -1.1 16 49 1977 2012 1988 1992 bottom-third 2011 18 71.7 72.6 -0.9 18 47 1977 2023 1991 1992 bottom-third 24 73.1 73.8 -0.7 26 37 1977 2013 1991 1992 normal 36 73.0 73.7 -0.7 20 41 1977 2001 1990 1992 bottom-third 1981,1986 48 73.0 73.7 -0.7 20 39 1979 2002 1991 1992 normal 1981,1984,1986,1994 60 73.1 73.7 -0.6 24 33 1977 2003,2013,2020,2021,2023 1992 1987 normal 1985,1987