Beach
Hamilton Beach
Hamilton, Canada · sea 21.1 °C at its warmest, in August

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020, sampled 16 km offshore, at the nearest open water cell of a 0.25° grid.
About
beach in Ontario, Canada
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 Hamilton Beach?
The sea off Hamilton Beach averages 21.1 °C at its warmest, in August, and 2.8 °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 Hamilton Beach?
The sea reaches 20 °C or more from August. Twenty degrees is where most swimmers stop calling water cold; below it, a wetsuit helps.
Where is Hamilton Beach?
Hamilton Beach is on the coast of Hamilton, Canada, at 43.2834, -79.7829. The map on this site flies straight to it.