Tonsai Beach — Sea temperature now
Rock-climbers' bay next to Railay.
Very warm water with a light chop and a light breeze — great swimming conditions.
Location
Tonsai Beach on the map, with nearby beaches and live sea temperatures.
7-day forecast
Water, air, waves, wind and UV outlook for the week ahead.
Monthly sea temperature averages
Typical year-round water temperature, based on regional climatology.
Best time to swim in Tonsai Beach
The sea in Tonsai Beach peaks in April, when the water averages around 30°C.
The main swimming season runs from January – December, when surface temperatures stay comfortable for extended sessions.
On average, 12 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
The coldest month is typically January at around 27°C, when cold-water swimmers dominate the coast.
Tonsai Beach sea temperature history
Long-term climatology for Tonsai Beach shows an annual mean sea temperature of 29°C, ranging from 27°C in winter to 30°C at the summer peak.
The seasonal swing is roughly 3°C between the coldest and warmest month — a useful yardstick when comparing years or checking whether the current sea is running above or below average.
Recent decades have trended slightly warmer at Tonsai Beach, in line with regional sea-surface temperature records for the wider basin.
Monthly averages below are drawn from multi-decadal climatology and are updated as new observations arrive.
Tonsai Beach sea temperature: frequently asked questions
What is the warmest month to swim in Tonsai Beach?
April is the warmest month in Tonsai Beach, when the sea averages about 30°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Tonsai Beach?
The coldest month in Tonsai Beach is typically January, when the water averages around 27°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Tonsai Beach without a wetsuit?
The main swimming season in Tonsai Beach runs from January – December — about 12 months a year when the sea sits above 20°C, the level most swimmers describe as pleasant without a wetsuit.
Do I need a wetsuit in Tonsai Beach?
Tonsai Beach stays warm year-round, so most swimmers never need a wetsuit — a rash guard is usually enough for sun and wildlife protection.
What is the average sea temperature in Tonsai Beach?
The long-term annual mean sea temperature in Tonsai Beach is about 29°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Tonsai Beach?
The live reading at the top of this page shows the current sea temperature in Tonsai Beach, updated hourly from marine buoy and satellite data. The 7-day forecast covers water, air, waves, wind and UV for the week ahead.
Year-round sea temperature
Best swim months: Jan – Feb – Mar – Apr – May – Jun – Jul – Aug – Sep – Oct – Nov – Dec
| Month | Sea | Comfort |
|---|---|---|
| Jan | 27°C | Hot |
| Feb | 28°C | Hot |
| Mar | 29°C | Hot |
| Apr ⭐ | 30°C | Hot |
| May | 30°C | Hot |
| Jun | 29°C | Hot |
| Jul | 29°C | Hot |
| Aug | 29°C | Hot |
| Sep | 29°C | Hot |
| Oct | 29°C | Hot |
| Nov | 28°C | Hot |
| Dec | 27°C | Hot |