Beach
Praia do Marciano
Ilhéus, Brazil · sea 28.4 °C at its warmest, in March

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020, sampled 21 km offshore, at the nearest open water cell of a 0.25° grid.
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 do Marciano?
The sea off Praia do Marciano averages 28.4 °C at its warmest, in March, and 25.3 °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 Marciano?
The sea reaches 20 °C or more from All year. Twenty degrees is where most swimmers stop calling water cold; below it, a wetsuit helps.
Where is Praia do Marciano?
Praia do Marciano is on the coast of Ilhéus, Brazil, at -14.7778, -39.0472. The map on this site flies straight to it.