Koh Tao Water Temperature
Updated Fri 12:40 (Asia/Bangkok)
Thailand · Forecast updated Sep 25, 2026, 12:40 UTC
Current Sea Temperature
29.4°C
84.9°F
Very warm water
Valid Sep 25, 2026, 12:40 (Asia/Bangkok). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
0.3°C below
The typical September average is 29.7°C (85.5°F) from the historical baseline.
Recent trend
Holding fairly steady
Seven-day average: 29.6°C, versus 29.5°C in the prior seven days.
What to wear
Very warm water
Swimwear is usually enough; a rash guard adds sun protection.
Cold tolerance varies. Wind, session length, sunshine, and exertion also affect comfort; temperature alone does not describe sea conditions or replace the snorkel forecast.
Typical Sea Temperature Over the Year
In the historical baseline for Koh Tao, typical monthly averages range from about 27.8°C (82.0°F) in January to 31.2°C (88.2°F) in May.
Over the past 30 days, the average sea temperature in Koh Tao has been 29.7°C.
Historical baseline (full year)
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Typical monthly sea-surface temperature near Koh Tao, calculated from hourly observations for 2023–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 27.3–28.8°C | 27.8°C / 82.0°F |
| February | 28.2–29.3°C | 28.7°C / 83.7°F |
| March | 28.8–29.7°C | 29.3°C / 84.7°F |
| April | 30.3–31.1°C | 30.7°C / 87.3°F |
| May | 30.9–31.8°C | 31.2°C / 88.2°F |
| June | 30.1–30.8°C | 30.4°C / 86.7°F |
| July | 30.0–30.2°C | 30.0°C / 86.0°F |
| August | 29.6–30.4°C | 30.0°C / 86.0°F |
| September | 29.6–29.8°C | 29.7°C / 85.5°F |
| October | 29.7–30.1°C | 29.9°C / 85.8°F |
| November | 29.0–29.7°C | 29.4°C / 84.9°F |
| December | 27.5–28.9°C | 28.3°C / 82.9°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (10.13, 99.88). Each month is the mean of yearly monthly means; the range is the lowest and highest of those yearly monthly means. Open-Meteo methodology.
Water temperature by month
Each month uses the 2023–2025 baseline. The range is the lowest and highest yearly monthly mean, not an hourly extreme.
Koh Tao in January
Typical January water temperature near Koh Tao is 27.8°C (82.0°F), with yearly monthly means from 27.3–28.8°C.
Koh Tao in February
Typical February water temperature near Koh Tao is 28.7°C (83.7°F), with yearly monthly means from 28.2–29.3°C.
Koh Tao in March
Typical March water temperature near Koh Tao is 29.3°C (84.7°F), with yearly monthly means from 28.8–29.7°C.
Koh Tao in April
Typical April water temperature near Koh Tao is 30.7°C (87.3°F), with yearly monthly means from 30.3–31.1°C.
Koh Tao in May
Typical May water temperature near Koh Tao is 31.2°C (88.2°F), with yearly monthly means from 30.9–31.8°C.
Koh Tao in June
Typical June water temperature near Koh Tao is 30.4°C (86.7°F), with yearly monthly means from 30.1–30.8°C.
Koh Tao in July
Typical July water temperature near Koh Tao is 30.0°C (86.0°F), with yearly monthly means from 30.0–30.2°C.
Koh Tao in August
Typical August water temperature near Koh Tao is 30.0°C (86.0°F), with yearly monthly means from 29.6–30.4°C.
Koh Tao in September
Typical September water temperature near Koh Tao is 29.7°C (85.5°F), with yearly monthly means from 29.6–29.8°C.
Koh Tao in October
Typical October water temperature near Koh Tao is 29.9°C (85.8°F), with yearly monthly means from 29.7–30.1°C.
Koh Tao in November
Typical November water temperature near Koh Tao is 29.4°C (84.9°F), with yearly monthly means from 29.0–29.7°C.
Koh Tao in December
Typical December water temperature near Koh Tao is 28.3°C (82.9°F), with yearly monthly means from 27.5–28.9°C.
Forecast archive (growing)
These values come from hourly forecasts SnorkelForecast has stored. They cover only months with records and do not replace the historical baseline.
| Month | Min | Average | Max |
|---|---|---|---|
| June | 30.0°C / 86.0°F | 30.5°C / 86.9°F | 31.1°C / 88.0°F |
| July | 29.8°C / 85.6°F | 30.3°C / 86.5°F | 30.9°C / 87.6°F |
| August | 29.6°C / 85.3°F | 29.9°C / 85.9°F | 30.4°C / 86.7°F |
| September | 29.2°C / 84.6°F | 29.6°C / 85.3°F | 30.4°C / 86.7°F |
Partial coverage: 4 calendar months with records. Profile calculated from 2805 hourly forecast records across 4 monthly periods. This is a growing archive, not a long-term climate normal.
About the water at Koh Tao
Gulf of Thailand island with shallow coral bays and resident green turtles.
- Area
- Surat Thani
Koh Tao Water Temperature: Common Questions
What is the water temperature in Koh Tao today?
The current sea surface temperature near Koh Tao is 29.4°C (84.9°F). Over the last 30 days, the average has been 29.7°C.
When is the water warmest in Koh Tao?
The water is typically warmest in May, at around 31.2°C (88.2°F) in the 2023–2025 historical baseline.
When is the water coldest in Koh Tao?
The water is typically coldest in January, at around 27.8°C (82.0°F) in the same historical baseline.
Can you swim in Koh Tao today?
At 29.4°C, the water is usually comfortable for swimming and snorkeling.
Full Snorkeling Forecast
See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Koh Tao.
View Snorkel Forecast →