Get the monthly weather forecast for Porto, Porto, Portugal, including daily high/low, historical averages, to help you plan ahead.

September weather in Porto Portugal. Daily high temperatures decrease by 4°F, from 75°F to 71°F, rarely falling below 64°F or exceeding 83°F.

September is a notable month of the summer season. Daytime temperatures are expected to be around 24°C, cooling off to about 17°C at night.

Porto has hot summers, pleasantly warm springs and autumns and winters which are mild but very wet.

Porto weather in September 2025. Expect 24°C daytime maximum temperatures in the shade with on average 8 hours of sunshine per day in Porto in September.

The weather in Porto in September is pleasantly warm and humid but cool, with average highs of 77°F (25°C) and lows of 59°F (15°C).

September weather forecast in Porto · 1 September. Sunday. +24°. +19° · 2 September. Monday. +23°. +19° · 3 September. Tuesday. +23°. +18° · 4 September.

There is a 57% chance of a perfect sunny day and a 43% chance of seeing some clouds, with on average 23mm of rainfall this month.

September in Porto. Max. temperature +34.6°C. Min. temperature +8.9°C. Monthly precipitation 52.1mm. Wind speed 23.85m/s.