Philadelphia in September
In September, Philadelphia averages 26°C (79°F) during the day and 17°C (62°F) at night, with frequent rain — about 14 days of the month see precipitation (101 mm total).
ShoulderConditions are comfortable for sightseeing without being sweltering. Plan for unsettled weather and bring rain gear.
It's peak hurricane season in Philadelphia during September. Travel is possible but expect storm risk, possible flight disruption, and generally lower travel insurance coverage.
How September compares to the rest of the year in Philadelphia
September is in the middle of the year for warmth in Philadelphia (4th of 12) and one of the driest months (10th of 12). Daytime temperature runs 8°C above the annual average (18°C). September runs 3°C cooler than August (29°C) and cools 6°C in October (20°C).
September sunrise & sunset in Philadelphia
Times shown for Philadelphia local time (America/New_York), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in Philadelphia — September
Golden-hour and blue-hour windows for the 15th of September, in Philadelphia's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — Philadelphia in September
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (Shoulder) and Philadelphia's popularity.
Crowds & pricing — September in Philadelphia
Philadelphia is in a shoulder season month — fewer crowds, slightly lower prices, and a calmer atmosphere than peak weeks. Most major sights stay open with normal hours, though a handful of seasonal restaurants or boat trips may run reduced schedules. Many regulars consider these months the best time to visit because you trade a small amount of weather reliability for a much more pleasant on-the-ground experience.
Why this tier: excellent tourism weather peak hazard season (1 active)
Sun & mosquito risk — September in Philadelphia
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Philadelphia in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 5°C / 41°F | -3°C / 26°F | 83 mm | 14 | — |
| February | 7°C / 45°F | -2°C / 28°F | 96 mm | 14 | — |
| March | 11°C / 52°F | 1°C / 34°F | 101 mm | 15 | — |
| April | 17°C / 63°F | 7°C / 44°F | 106 mm | 17 | — |
| May | 23°C / 73°F | 13°C / 55°F | 108 mm | 17 | — |
| June | 28°C / 82°F | 18°C / 64°F | 107 mm | 17 | — |
| July | 30°C / 87°F | 21°C / 70°F | 123 mm | 19 | — |
| August | 29°C / 85°F | 20°C / 68°F | 106 mm | 18 | — |
| September | 26°C / 79°F | 17°C / 62°F | 101 mm | 14 | — |
| October | 20°C / 67°F | 11°C / 51°F | 106 mm | 15 | — |
| November | 13°C / 55°F | 4°C / 38°F | 79 mm | 11 | — |
| December | 8°C / 47°F | 0°C / 33°F | 111 mm | 12 | — |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for Philadelphia in September →
Frequently asked questions
How hot is Philadelphia in September?
In September, Philadelphia averages a high of 26°C (79°F) and a low of 17°C (62°F) — generally warm.
Does it rain a lot in Philadelphia in September?
September can be fairly wet in Philadelphia, with about 14 rainy days on average.
Is September a good time to visit Philadelphia?
September is warm but on the rainy side. It suits travelers who are comfortable with warm weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for Philadelphia in September?
Pack light layers for warm days and cooler evenings, plus a compact umbrella or rain jacket. See the full September packing list for Philadelphia for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.