Porto weather in September
September in Porto: warm, a little rain, with very humid — an excellent time to visit.
#5 of 12 months in Porto · #179 of 604 destinations to visit in September · comfort 86/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Porto climate normals — September
| Daytime high | 24°C / 75°F | 🌤 warm |
|---|---|---|
| Nighttime low | 17°C / 62°F | |
| Feels like (high) | 25°C / 77°F | |
| Rainfall | 77 mm / 3 in | 🌦 some rain |
| Rainy days | 10 days | |
| Humidity | 81% | 💦 very humid |
| Dew point | 16°C / 61°F | |
| Sunshine | 10.3 h/day | |
| Daylight | 12.5 h | |
| Wind | 16 km/h / 10 mph | |
| Air quality (US AQI) | 51 | 🙂 moderate |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Porto in September — FAQ
- Is September a good time to visit Porto?
- September in Porto: warm, a little rain, with very humid — an excellent time to visit. It ranks #5 of 12 months for Porto on SeasonMap's comfort score (86/100).
- What is the weather like in Porto in September?
- In September, Porto averages a daily high of 24.1°C and a low of 16.5°C, with about 77 mm of rain over roughly 9.8 rainy days.
- What is the air quality in Porto in September?
- Porto has a mean US Air Quality Index of about 51 in September.