Dry season, monsoon and shoulder months explained month by month — temperatures, rainfall, diving conditions, what to pack and how the weather affects each dive site.
27 February 2024 · updated 9 October 2025 · by Bryan Roseman
In short. The weather in Koh Tao features two main seasons: dry season (March–October) and monsoon season (November–January). The best weather in Koh Tao occurs during the dry season, with minimal rain and over 300 sunny days a year. Average temperatures range from 25–35°C, making it ideal for diving and beach activities year-round.
Understanding the weather in Koh Tao is essential for planning the perfect diving vacation or beach getaway. Thailand’s premier diving destination enjoys a tropical climate with warm temperatures and distinct seasonal patterns that directly impact diving conditions, visibility and the overall travel experience.
Whether you’re planning to get certified, take advanced courses, or simply enjoy the underwater world, knowing when to visit based on the weather in Koh Tao will help you make the most of your adventure. Learn more about the best time to dive in Koh Tao for specific diving conditions.
The weather in Koh Tao follows a simple two-season pattern with dry and monsoon periods, plus shoulder months that offer unique advantages for travellers and divers.
The ideal weather in Koh Tao, with minimal rainfall, sunny skies and excellent diving conditions. Peak diving season, with calm seas and consistent weather patterns.
Unpredictable weather in Koh Tao with frequent rain and occasional storms. Lower tourist numbers and potential diving cancellations, but also fewer crowds and lower prices.
Transition periods with mixed weather in Koh Tao. Great value for money, with fewer crowds, moderate prices and generally good diving conditions.
Each month brings different weather patterns in Koh Tao. Use this guide to plan your diving adventure:
| Month | Temperature | Rainfall | What to expect |
|---|---|---|---|
| January | 24–28°C | Frequent rain | End of monsoon season |
| February | 25–29°C | Decreasing rain | Shoulder month – great value |
| March | 27–32°C | Minimal rain | Dry season begins |
| April | 28–34°C | Very low rain | Perfect diving weather |
| May | 28–34°C | Minimal rain | Excellent conditions |
| June | 28–33°C | Low rain | Peak dry season |
| July | 27–33°C | Occasional showers | Warm and sunny |
| August | 27–32°C | Brief rain periods | Continued dry season |
| September | 26–31°C | Light showers | Still excellent diving |
| October | 26–30°C | Low rain | End of dry season |
| November | 25–29°C | Increasing rain | Shoulder month transition |
| December | 24–28°C | Heavy rain periods | Peak monsoon season |
Use these questions to work out the best time to visit based on your preferences:
Match your answers against the seasons above: if you want minimal rain and don’t mind crowds, come in the dry season; if you prefer fewer people and a lower budget, the shoulder months or monsoon season will suit you better.
| Season | Visibility | Sea conditions | Water temperature | Best for |
|---|---|---|---|---|
| Dry season (Mar–Oct) | 20–30 m | Calm seas, minimal current | 27–30°C | All dive levels, consistent conditions |
| Monsoon season (Nov–Jan) | 10–20 m | Variable, possible cancellations | 24–28°C | Experienced divers, flexibility needed |
| Shoulder months (Feb & Nov) | 15–25 m | Generally good, some variability | 25–29°C | Great value, moderate crowds |
The weather in Koh Tao directly affects access to different dive sites. Here’s how seasonal conditions impact the most popular locations:
Each dive site offers unique marine life encounters that can vary with seasonal weather patterns and water conditions.
To maximise your experience, consider these factors when planning based on weather in Koh Tao:
La Bombona Diving operates year-round, adapting to the weather in Koh Tao to ensure safe, enjoyable diving. Our instructors understand how weather patterns affect diving conditions and will guide you to the best sites based on the conditions on the day, whether you visit in dry-season perfection or for a monsoon-season adventure. Don’t let weather uncertainty stop your diving adventure — book your Open Water course: 11,000 ฿, 4 ocean dives over 4 days, all weather conditions considered.
The best weather in Koh Tao for diving is during the dry season from March to October. This period offers minimal rainfall, calm seas, excellent visibility (20–30 m) and warm water temperatures (27–30°C). Peak months are April through August, when conditions are most consistent and predictable for diving.
Monsoon season (November–January) doesn't mean you should avoid Koh Tao entirely. While the weather in Koh Tao during this period includes frequent rain and possible dive cancellations, you'll also enjoy fewer crowds, lower accommodation prices and some clear diving days. It's perfect for budget travellers who can be flexible with their plans.
During dry season, the weather in Koh Tao can reach temperatures of 30–35°C (86–95°F), with the hottest months being April through July. Despite the heat, the constant sea breeze and warm water make it comfortable for diving and beach activities. Many visitors actually prefer these warmer months for the consistently sunny skies.
Shoulder months offer some of the best value for weather in Koh Tao. February marks the transition from monsoon to dry season, with decreasing rainfall and pleasant 25–29°C temperatures. November is the opposite transition, with increasing rain but still many good diving days. Both months have fewer crowds and moderate accommodation prices.
Yes, weather conditions directly impact which dive sites are accessible. During dry season (March–October), all sites including Sail Rock are regularly accessible, with calm seas. During monsoon season, operators may cancel trips to distant sites like Sail Rock due to rough seas, but closer sites like Japanese Gardens and Green Rock remain diveable on calmer days.
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