Lamai Beach — Sea temperature now
Coastal beach in Koh Samui.
Very warm water with a light chop and a light breeze — great swimming conditions.
Location
Lamai 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 Lamai Beach
The sea in Lamai 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.
Lamai Beach sea temperature history
Long-term climatology for Lamai 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 Lamai 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.
Lamai Beach sea temperature: frequently asked questions
What is the warmest month to swim in Lamai Beach?
April is the warmest month in Lamai Beach, when the sea averages about 30°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Lamai Beach?
The coldest month in Lamai Beach is typically January, when the water averages around 27°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Lamai Beach without a wetsuit?
The main swimming season in Lamai 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 Lamai Beach?
Lamai 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 Lamai Beach?
The long-term annual mean sea temperature in Lamai Beach is about 29°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Lamai Beach?
The live reading at the top of this page shows the current sea temperature in Lamai 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 |