Beach
Sugar Beach
Soufrière Quarter, Saint Lucia · sea 29.1 °C at its warmest, in September

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020.
About
beach in Saint-Lucia
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 Sugar Beach?
The sea off Sugar Beach averages 29.1 °C at its warmest, in September, and 26.7 °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 Sugar Beach?
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 Sugar Beach?
Sugar Beach is on the coast of Soufrière Quarter, Saint Lucia, at 13.8279, -61.0617. The map on this site flies straight to it.