Philadelphia weather in September
Philadelphia in September averages 21°C (70°F), 112 mm of rain and 7 hours of sun a day.
Of the twelve months in Philadelphia, September is the fourth warmest and the wettest.
- Average temp
- 21°C (70°F)
17–26°C · 62–79°F
- Rainfall
- 112 mm
Showers likely
- Sunshine
- 7 h
hours per day
- Wind
- 13 km/h
What is Philadelphia like in September?
Daytime
Days are warm, typically in the mid-20s°C or above.
Rain
Some rain is likely; pack for showers.
Evening
Evenings are cooler. A layer helps after sunset.
What should I pack for Philadelphia in September?
A light rain jacket
About 112 mm falls this month — showers rather than washouts.
A layer for the evening
Evenings cool off noticeably once the sun is down.
September compared with August and October
September in Philadelphia is 3.9°C cooler than August and about as wet as it, which averages 25°C (77°F).
September in Philadelphia is 6.5°C warmer than October and 23 mm wetter than it, which averages 15°C (58°F).
Daylight in Philadelphia in September
On 15 September the sun is up for 12 hours 26 minutes in Philadelphia, rising about 06:42 and setting about 19:08 local time.
September ends 1 hour 15 minutes shorter than it begins, so the last week of the month is a different length of day from the first.
That is 2 hours 34 minutes short of June, the longest-lit month here.
Where to stay in Philadelphia
Dates are a starting point for September.
Travel guides for Philadelphia
What to read before you book.
Philadelphia weather by month
TemperatureRainfall
How September compares with the rest of the year
September is highlighted. Every other month links to its own page.
| Month | Average | Rainfall |
|---|---|---|
| January | 1°C / 34°F | 79 mm |
| February | 2°C / 36°F | 69 mm |
| March | 7°C / 44°F | 101 mm |
| April | 13°C / 55°F | 88 mm |
| May | 18°C / 65°F | 86 mm |
| June | 23°C / 74°F | 103 mm |
| July | 26°C / 79°F | 111 mm |
| August | 25°C / 77°F | 109 mm |
| September | 21°C / 70°F | 112 mm |
| October | 15°C / 58°F | 88 mm |
| November | 9°C / 48°F | 74 mm |
| December | 4°C / 39°F | 101 mm |
Similar weather in September
Other destinations whose September averages sit close to this one.
Check another month
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FAQs about Philadelphia in September
September climate averages for Philadelphia, 1991–2020.
Philadelphia averages 21°C (70°F) in September, ranging from about 17°C (62°F) at night to 26°C (79°F) in the afternoon. That is a 1991–2020 average, so an individual week can run either side of it.
Some. About 112 mm falls across September, enough to need a light jacket but not enough to reshape a trip.
Yes. September averages 21°C (70°F) against 15°C (58°F) in October — 6.5°C warmer.
September is 3.9°C cooler than August, and about as wet.
Yes. September falls inside the most comfortable stretch of the year here, May to October, on temperature and rainfall together.
About 7 hours of sun a day on the 1991–2020 average.
This page does not show today's weather. It is a 1991–2020 climate normal from Meteostat — a long-run average of what September is usually like, which is what you want when booking months ahead. For today or the coming week, check a live forecast.
About 12 hours 26 minutes of daylight in mid-September, against 15 hours in June and 9 hours 21 minutes in December.
On 15 September, sunrise is about 06:42 and sunset about 19:08 local time. Both shift across the month — the month ends 1 hour 15 minutes shorter than it starts.
