Beach
Railay Beach
Ao Nang, Thailand · sea 30.3 °C at its warmest, in May

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
Railay (Thai: ไร่เลย์, pronounced [râj lēː]), also known as Rai Leh, is a small peninsula between the city of Krabi and Ao Nang in Thailand.
Questions
How warm is the sea at Railay Beach?
The sea off Railay Beach averages 30.3 °C at its warmest, in May, and 28.3 °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 Railay 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 Railay Beach?
Railay Beach is on the coast of Ao Nang, Thailand, at 8.0106, 98.8394. The map on this site flies straight to it.