Weather in Porto in September 2025
Average weather
Average temperature in Porto in September
The expected average maximum temperature in September is +23°C with a maximum of +31°C and a minimum of +11°C.
The average maximum temperature goes up 40% by the end of the month, compared with the beginning of the month, from +23°C to +31°C.
Is Porto warm or cold in September?
Porto is typically warm in September.
Maximum temperatures go down compared to the previous month from +24°C to +23°C. The minimum temperature also goes down from +17°C to +16°C.
It’s generally warm, but pack a long-sleeve shirt for evenings.
September is one of the warmest months in Porto, here is the comparison with other months:
Water temperature in Porto in September
Water in Porto in September is Fresh. It varies from +17°C to +20°C, with an average of +18°C. This is almost similar to the air temperature, which averages +23°C.
The water temperature in September is one of the warmest of the entire year:
Can you swim in Porto in September?
Climate in Porto in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +24°C | +23°C | +20°C | ||||
| Min. temperature | ||||||
| +10°C | +7°C | +3°C | ||||
| Max. temperature | ||||||
| +38°C | +36°C | +32°C | ||||
| Rainfall | ||||||
| 18 mm | 55 mm | 145 mm | ||||
| Wind | ||||||
| 2 m/s | 2 m/s | 2 m/s | ||||
| Avg. water temperature | ||||||
| +18°C | +18°C | +18°C | ||||
| Humidity | ||||||
| 77% | 77% | 78% | ||||
| Air pressure | ||||||
| 1016 HPa | 1016 HPa | 1015 HPa | ||||
| Sunny days | ||||||
| 14 | 12 | 10 | ||||
| Cloudy days | ||||||
| 11 | 8 | 6 | ||||
| Rainy days | ||||||
| 5 | 9 | 14 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
September weather is still as good as in August. It’s getting colder in September. From +24°C in the day, the average maximum temperature lowers to +23°C. Prepare for more rain. Average rainfall goes from 18 mm to 55 mm. Humidity levels don’t change as the month goes on, averaging around 77%. The average wind speed doesn’t change much during September, staying around 2 m/s. The days becoming less sunny, going from 14 sunny days in August to 12 in September.
Next month (October) brings a further decline in the weather.
Wind
The average wind speed is 3 m/s getting up to 8 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Porto is gradually decreasing during September, going from 3 m/s to 2 m/s over the course of the month.
Rain
How was the weather last September in Porto?
Climate Change over Years
The climate in Porto in September has not changed much over the last 43 years.
The average temperature was the lowest in 1979 (+17°C) and the highest in 2022 (+20°C). The driest year was 2007 with only 565 mm of rainfall, and the wettest year was 2022 with 1854 mm.
FAQ
Is September a good time to visit Porto?
Can you sunbathe in Porto in September?
Can you swim in Porto in September?
Is Porto rainy in September?
Is it sunny in Porto in September?
Other cities in Portugal
Monthly weather in Porto
Source of the data
For this page, we’ve looked at the typical weather in Porto, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.