when will the weather cool down in philadelphia?
The hottest day of the year is July 20, with an average high of 87°F and low of 70°F. The cold season lasts for 3.1 months, from December 1 to March 6, with an average daily high temperature below 49°F. The coldest day of the year is January 30, with an average low of 26°F and high of 40°F.