Beach
Cemetery Beach
Tasmania, Australia · sea 16.4 °C at its warmest, in February

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020, sampled 13 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 Cemetery Beach?
The sea off Cemetery Beach averages 16.4 °C at its warmest, in February, and 12 °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 Cemetery Beach?
The sea here never averages 20 °C in any month, so swimming means cold water all year. Some people do it anyway.
Where is Cemetery Beach?
Cemetery Beach is on the coast of Tasmania, Australia, at -43.3400, 147.2200. The map on this site flies straight to it.