- Sunshine hrs/yr
- 2,160
- Snowfall
- N/A – tropical island; no snow.
Updated July 2026 · Sources cited: weather-and-climate.com, saireecottagediving.com
Good to know
Good to Know
- February–March offer the most comfortable conditions with lowest temperatures (still 26–29°C (79–84°F)) and excellent diving visibility (20–30m+).
- Despite being called the 'wet season,' November–January rarely see all-day rain; thunderstorms typically occur in late afternoon and last a few hours.
- March–May are the hottest months; if you dislike extreme heat (35–36°C (97°F)), visit Jan–Feb or Jun–Oct instead.
- Koh Tao's central location in the Gulf of Thailand provides some shelter; one side of the island remains calm even during monsoon, allowing year-round diving on sheltered west-coast sites.
- November is the cheapest month for accommodation due to monsoon; tourist numbers are lowest. Best value + fewer crowds if you tolerate rain.
- Water temperature varies only ~8°C (46°F) across the year (26–30°C (79–86°F)); most visitors use a light 3mm wetsuit or rash vest year-round.
- Weather prediction is unreliable on Koh Tao due to its isolated position; even forecasts 1–2 weeks out can shift. Check locally before booking outdoor activities.
- Whale shark sightings are most likely March–May and again in November, though never guaranteed. Visiting during these months increases odds.
Seasons
Best Season – Hot & Dry
- Months
- February to May
- Rainfall Monthly Mm
- 38
- Rainfall Rainy Days
- 5
- Description
- Blue skies, minimal rainfall, very sunny conditions. March and April are the hottest months, with daytime highs reaching 35–36°C (97°F) and occasional humidity of 85–90%. Water temperature rises to 30°C (86°F). Peak tourist season; best visibility for diving (20–30m+).
Temperature Range
- Night Low Celsius
- 22
- Daytime Low Celsius
- 28
- Daytime High Celsius
- 33
- Night Low Fahrenheit
- 72
- Daytime Low Fahrenheit
- 82
- Daytime High Fahrenheit
- 91
Windy Season
- Months
- June to October
- Rainfall Monthly Mm
- 120
- Rainfall Rainy Days
- 15
- Description
- Southwest winds arrive bringing occasional showers and cooler ocean breezes. Occasional heavy rainfall, especially May–June and September. Water temperature averages 29°C (84°F). Less crowded; some wind-affected days but still diveable. Visibility typically 15–20m.
Temperature Range
- Night Low Celsius
- 22
- Daytime Low Celsius
- 25
- Daytime High Celsius
- 34
- Night Low Fahrenheit
- 72
- Daytime Low Fahrenheit
- 77
- Daytime High Fahrenheit
- 93
Worst Season – Monsoon/Wet
- Months
- November to January
- Rainfall Monthly Mm
- 200
- Rainfall Rainy Days
- 20
- Description
- Heaviest rainfall peaks in November and early December (up to 311mm/month in October). Heavy afternoon thunderstorms are common but typically brief (a few hours). Monsoon usually ends by January. Cooler temperatures (reaching lows of 26–28°C (82°F)). Water temperature drops to 26–28°C (82°F). Fewer tourists; significantly cheaper accommodation. Visibility reduced to 5–10m during heavy rain periods; still diveable with sheltered west-coast sites.
Temperature Range
- Night Low Celsius
- 22
- Daytime Low Celsius
- 26
- Daytime High Celsius
- 30
- Night Low Fahrenheit
- 72
- Daytime Low Fahrenheit
- 79
- Daytime High Fahrenheit
- 86
Overview
Koh Tao has a tropical climate with warm weather year-round and three distinct seasons: hot and dry (Feb–May), hot and windy (Jun–Oct), and wet/monsoon (Nov–Jan). Temperatures remain relatively stable between roughly 25–36°C (77–97°F) throughout the year.
Snowfall
N/A – tropical island; no snow.
Humidity Note
High year-round (80–90% typical), especially in hot season. Evening breezes and ocean proximity provide relief.
Sunshine Hours
- Annual Total
- 2160
- Sunniest Month
- March (240 hours)
- Cloudiest Month
- September (146 hours)
Water Temperature
- Coolest Months
- December–January
- Warmest Months
- April–May
- Coolest Celsius
- 26
- Warmest Celsius
- 30
- Coolest Fahrenheit
- 79
- Warmest Fahrenheit
- 86
Annual Rainfall Mm
1794
Peak Off Peak Summary
- Peak Months
- December–March (coolest part of dry season; Christmas/New Year holidays)
- Shoulder Low
- September–October (transition to monsoon; good value)
- Shoulder High
- April (hot but still dry; whale shark season)
- Off Peak Months
- May, November
AI-generated estimateData refreshed July 2026
Sources cited for this category
These are the sources cited in this climate & weather research for this city. Individual figures may not each trace to one of them.
More About Koh Tao
Data last updated July 2026 · Verify anything important.