Beach
Kata Noi beach
Phuket, Thailand · sea 29.9 °C at its warmest, in May

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020, sampled 21 km offshore, at the nearest open water cell of a 0.25° grid.
About
Hat Kata Noi (Thai: หาดกะตะน้อย, pronounced [hàːt kā.tàʔ nɔ́ːj]; Noi meaning 'little' in Thai) is a beach on the southwest side of the island of Phuket in Thailand.
Questions
How warm is the sea at Kata Noi beach?
The sea off Kata Noi beach averages 29.9 °C at its warmest, in May, and 28.4 °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 Kata Noi 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 Kata Noi beach?
Kata Noi beach is on the coast of Phuket, Thailand, at 7.8064, 98.2989. The map on this site flies straight to it.