Porto weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Excellent
Best time to visit: May – September
What is the weather like in Porto in September?
In September, Porto is warm: daytime highs average 24 °C, and nights cool down to about 16 °C. The sea averages 17.4 °C – bracing, so a wetsuit helps for longer swims. The sun shines for around 9 hours a day. Rain falls on about 7 days, adding up to 65 mm. All in all, September is an excellent month for a holiday in Porto.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 100 | 92 | 72 |
| Day | 26° | 24° | 21° |
| Night | 17° | 16° | 14° |
| Sea | 17° | 17° | 17° |
| Sun | 10 h | 9 h | 6 h |
| Rain days | 4 | 7 | 13 |
More details for September
- Daylight
- 12 h 32 min07:14 – 19:46
- UV index
- 6 · highclear sky, noon (estimate)
- Muggy days
- 1 daydew point 18 °C or more
- Wind
- 16 km/haverage daily peak
- Cloud cover
- 46 %on average
- Hot days
- 3 days30 °C or more
- Time zone
- UTC+1Europe/Lisbon
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %93 %
- Few rainy daysweight 30 %79 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Wetsuit for longer swims
- Sunscreen
- Sunglasses & sun hat
Porto in September: quick answers
Is Porto hot in September?
Warm rather than hot: in September, daytime highs in Porto average 24 °C and nights cool to about 16 °C. On about 3 days the thermometer climbs to 30 °C or more.
Can you swim in Porto in September?
Only if you don't mind cold water: in September the sea averages just 17.4 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Porto in September?
Rain falls on about 7 days, adding up to 65 mm.
Porto month by month
The whole year in PortoAll destinations: Portugal
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, GeoNames (CC BY 4.0)