Pittsburgh weather in September
September in Pittsburgh: warm, rainy, with clean air — one of the best months to visit.
#2 of 12 months in Pittsburgh · #144 of 604 destinations to visit in September · comfort 87/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Pittsburgh climate normals — September
| Daytime high | 25°C / 77°F | 🌤 warm |
|---|---|---|
| Nighttime low | 15°C / 60°F | |
| Feels like (high) | 26°C / 79°F | |
| Rainfall | 93 mm / 3.7 in | 🌧 rainy |
| Rainy days | 10 days | |
| Humidity | 77% | 💦 very humid |
| Dew point | 14°C / 58°F | |
| Sunshine | 9.1 h/day | |
| Daylight | 12.5 h | |
| Wind | 13 km/h / 8 mph | |
| Air quality (US AQI) | 43 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Pittsburgh in September — FAQ
- Is September a good time to visit Pittsburgh?
- September in Pittsburgh: warm, rainy, with clean air — one of the best months to visit. It ranks #2 of 12 months for Pittsburgh on SeasonMap's comfort score (87/100).
- What is the weather like in Pittsburgh in September?
- In September, Pittsburgh averages a daily high of 24.9°C and a low of 15.4°C, with about 92.8 mm of rain over roughly 10.4 rainy days.
- What is the air quality in Pittsburgh in September?
- Pittsburgh has a mean US Air Quality Index of about 43 in September.