1991-2020 Degrees Fahrenheit 1 52.6 51.2 1.4 53 23 1968 2018 1989 1991 top-third 2 49.9 49.4 0.5 47 28 1978 1950 1988 1991 normal 3 50.5 49.6 0.9 53 22 1977 1950 1990 1991 top-third 1997 4 51.2 51.1 0.1 42 32 1977 2017 1988 1991 normal 1987 5 54.1 54.1 0.0 43 31 1977 2017 1990 1991 normal 6 57.7 57.8 -0.1 46 28 1977 2017 1990 1991 normal 1955,1983 7 60.9 61.2 -0.3 43 31 1977 2017 1990 1991 normal 1983 8 63.6 63.8 -0.2 46 28 1977 2017 1990 1991 normal 1959,1989,2007 9 65.2 65.6 -0.4 41 33 1977 2017 1990 1991 normal 1983,2002,2011 10 66.2 66.3 -0.1 50 24 1977 2017 1990 1991 top-third 1959,2000,2006,2011 11 66.4 66.1 0.3 54 20 1977 2017 1990 1991 top-third 1986 12 65.8 65.4 0.4 55 19 1977 2017 1990 1991 top-third 1986,2022 18 63.6 62.9 0.7 61 11 1977 2017 1991 1975 top-third 1999 24 66.1 65.4 0.7 63 9 1977 2017 1991 1992 top-third 2022 36 65.6 65.3 0.3 59 11 1970 2018 1991 1957 top-third 1952,1956,2014 48 65.4 65.3 0.1 52 16 1970 2019,2020 1991 1975 top-third 1974,1975 60 65.2 65.3 -0.1 45 21 1970 2020 1991 1991 top-third 1991,2007