Beach
Praia da Lada
Portugal · sea 17.4 °C at its warmest, in August

Sea temperature month by month
13.9Jan
13.4Feb
13.6Mar
14.4Apr
15.5May
16.7Jun
17.1Jul
17.4Aug
17.3Sep
16.8Oct
15.8Nov
14.6Dec
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020.
Wikipedia has no article about this beach yet. It is on the atlas from its Wikidata record and its photograph.
Questions
How warm is the sea at Praia da Lada?
The sea off Praia da Lada averages 17.4 °C at its warmest, in August, and 13.4 °C at its coolest. These are monthly means from NOAA's OISST v2.1 satellite and buoy record for 1991 to 2020, sampled at the beach's own coordinates.
When can you swim at Praia da Lada?
The sea here never averages 20 °C in any month, so swimming means cold water all year. Some people do it anyway.
Where is Praia da Lada?
Praia da Lada is on the coast of Portugal, at 41.3891, -8.7750. The map on this site flies straight to it.