Portugal: where to swim in September?
Portugal, in September: the sea is at 20.2 °C on average along the coast, from 18.4 °C to 22.1 °C depending on the spot. Where the water is warmest (22.1 °C), it is pleasant. You can swim for a long time without shivering.
Sea temperature, month by month
| Month | Average temperature | Depending on the spot | Where it is warmest |
|---|---|---|---|
| January | 15.6 °C | 14.3 °C – 17.1 °C | cool |
| February | 14.9 °C | 13.8 °C – 16.3 °C | cool |
| March | 14.9 °C | 13.8 °C – 16.3 °C | cool |
| April | 16.0 °C | 15.1 °C – 17.2 °C | cool |
| May | 17.2 °C | 16.0 °C – 18.8 °C | cool |
| June | 18.5 °C | 17.4 °C – 20.2 °C | pleasant |
| July | 19.2 °C | 17.9 °C – 21.2 °C | pleasant |
| August | 19.5 °C | 18.1 °C – 21.3 °C | pleasant |
| September | 20.2 °C | 18.4 °C – 22.1 °C | pleasant |
| October | 19.6 °C | 17.5 °C – 21.8 °C | pleasant |
| November | 18.1 °C | 16.5 °C – 19.9 °C | pleasant |
| December | 16.7 °C | 15.0 °C – 18.2 °C | cool |
Compared with August, the water warms up by 0.7 °C in September. The warmest month: September (20.2 °C). The coldest: February (14.9 °C).
Nearby, in September
- France 20.1 °C · warm
- Ireland 15.0 °C · cool
- United Kingdom 14.3 °C · cool
- Netherlands 17.7 °C · cool
- Germany 17.0 °C · cool
- Croatia 24.1 °C · warm
And right now?
For the temperature measured right now, station by station and to the hour: Portugal: water temperature
Frequently asked questions
What is the sea temperature in September?
Portugal, in September: 20.2 °C on average along the coast, from 18.4 °C in the coolest waters to 22.1 °C in the warmest (average of the years 2011 to 2025).
Can you swim in September?
Where the water is warmest (22.1 °C), it is pleasant. You can swim for a long time without shivering.
What is the best month for swimming?
The water is warmest in September (20.2 °C on average) and coldest in February (14.9 °C). Where the water is warmest, it goes above 20 °C in these months: June, July, August, September, October.
Where is the water warmest in September?
The warmest in September: France (20.1 °C), Ireland (15.0 °C), United Kingdom (14.3 °C). The coolest: Croatia (24.1 °C).
Where do these temperatures come from?
These are averages of the sea surface temperature from 2011 to 2025, computed from NOAA satellite images (OISST, one value about every 50 km), in a 100 km strip along the coasts of the main country: distant territories (overseas, remote islands) are not counted. It is an estimate, not a measurement taken at the beach: lakes and rivers are not included.