Beach
Nidos
Lithuania · sea 18.9 °C at its warmest, in August

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020.
About
bathing placelocated on the Lithuanian coast in the municipality/city Neringos in the region of Klaipedos
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 Nidos?
The sea off Nidos averages 18.9 °C at its warmest, in August, and 2.5 °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 Nidos?
The sea here never averages 20 °C in any month, so swimming means cold water all year. Some people do it anyway.
Where is Nidos?
Nidos is on the coast of Lithuania, at 55.3159, 20.9848. The map on this site flies straight to it.