Wilmington, Delaware, Average Temperature Rankings, July 2012 1991-2020 Degrees Fahrenheit 1 80.3 77.6 2.7 72 4 1962 1955 2010 2011 top-tenth 2 76.3 75.2 1.1 66 10 1979 2010 2009 2011 top-third 2013 3 73.2 71.3 1.9 73 3 1967 2010 2009 2011 top-tenth 2019 4 68.3 67.0 1.3 71 5 1967 2010 2009 2011 top-tenth 5 64.9 62.2 2.7 72 2 1950 2010 2011 2010 top-tenth 6 60.7 57.8 2.9 73 1 1978 2012 2011 2012 highest 7 57.4 54.3 3.1 73 1 1978 2012 2011 2012 highest 8 55.4 52.3 3.1 72 1 1978 2012 2011 2012 highest 9 54.7 51.7 3.0 71 1 1978 2012 2011 2012 highest 10 54.9 52.3 2.6 71 1 1978 2012 2011 2012 highest 11 56.2 53.8 2.4 71 1 1978 2012 2011 2012 highest 12 57.8 55.6 2.2 71 1 1978 2012 2011 2012 highest 18 58.3 56.4 1.9 69 1 1968 2012 2011 2012 highest 24 56.7 55.6 1.1 65 3 1978 2017 2011 2012 top-tenth 2021,2022 36 56.5 55.6 0.9 59 5 1979 2018,2022 2011 2012 top-tenth 48 55.9 55.5 0.4 53 7 1968,1970,1980 2019,2022 2011 2009 top-third 2008,2009 60 56.0 55.4 0.6 52 5 1967,1968,1970 2020 2011 2002 top-tenth 2002