Beach
Praia do Tonel
Sagres, Portugal · sea 19.7 °C at its warmest, in September

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020, sampled 15 km offshore, at the nearest open water cell of a 0.25° grid.
About
A Praia do Tonel é uma praia em Sagres, município de Vila do Bispo, entre a praia do Beliche e a vila de Sagres.
Questions
How warm is the sea at Praia do Tonel?
The sea off Praia do Tonel averages 19.7 °C at its warmest, in September, and 15.2 °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 do Tonel?
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 do Tonel?
Praia do Tonel is on the coast of Sagres, Portugal, at 37.0058, -8.9480. The map on this site flies straight to it.