Beach
Spiaggia Marina di Massa
Italy · sea 25.2 °C at its warmest, in August

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020, sampled 14 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 Spiaggia Marina di Massa?
The sea off Spiaggia Marina di Massa averages 25.2 °C at its warmest, in August, and 13.3 °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 Spiaggia Marina di Massa?
The sea reaches 20 °C or more from June to October. Twenty degrees is where most swimmers stop calling water cold; below it, a wetsuit helps.
Where is Spiaggia Marina di Massa?
Spiaggia Marina di Massa is on the coast of Italy, at 44.0025, 10.1052. The map on this site flies straight to it.