Philadelphia weather in September
Long-run climate averages for Philadelphia, PA in September, plus what the forecast models say for the days ahead.
In September, Philadelphia averages 77°F by day and 60°F at night. The wettest month is usually July.
September in Philadelphia averages a daytime high of 77°F and an overnight low of 60°F, which reads as warm for this part of the world. Across the whole year Philadelphia sees roughly 48 inches of precipitation.
Climate averages tell you what to pack. They do not tell you what next Tuesday looks like - for that, see the live Philadelphia forecast with every model compared and how much they currently agree.
Philadelphia weather by month
what to expect in Philadelphia through the year, 1991-2020 averagesHere is Philadelphia's typical weather in each month: the average daytime high and overnight low in °F, how each month feels, and the wettest month marked. Use it to plan any trip to Philadelphia by season.
Bottom line: over the last 30 days the European model has been the most accurate forecast for Philadelphia, scoring 96/100 on our CheckWeather Score, ahead of the American at 80. See the full US accuracy scoreboard for exactly how every model is tested.
Common questions
How warm is Philadelphia in September?
Is September a good time to visit Philadelphia?
Does it rain a lot in Philadelphia in September?
Climate averages from ERA5 reanalysis. Model accuracy re-scored over a rolling 30 days. Page updated .