Thailand´s climate varies significantly from north to south, but for divers, the focus is on the southern peninsula, where warm tropical conditions prevail year-round. With average temperatures between 24°C and 30°C (75°F to 86°F), the region offers inviting seas and popular spots like Koh Tao, Koh Phangan, Koh Samui, Phuket, and the Similan Islands. Understanding the seasonal patterns here is key to choosing the best time to dive in Thailand.
The rainy season still offers warm waters but comes with higher humidity and occasional storms, so timing your trip carefully will help ensure the best conditions. A key piece of information to know: In Thailand, the rainy season isn’t all over the country at the same time. There are two rainy seasons. While the part of Thailand from Chiang Mai to Phuket via Bangkok (Northern, Central and Andaman Coast) has its rainy season from May to October, the Gulf of Thailand (Koh Samui and Koh Tao) has its rainy season from October to January.
Thailand average weather
You will find below, month by month, the average weather conditions in Thailand:
Thailand average temperatures
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
| max | 32°C 89°F | 33°C 91°F | 34°C 93°F | 35°C 95°F | 34°C 94°F | 33°C 92°F | 33°C 91°F | 33°C 91°F | 32°C 90°F | 32°C 89°F | 32°C 89°F | 31°C 88°F |
| min | 22°C 72°F | 24°C 75°F | 26°C 78°F | 27°C 80°F | 27°C 80°F | 27°C 80°F | 26°C79°F | 26°C79°F | 26°C78°F | 26°C78°F | 24°C76°F | 22°C72°F |
Thailand average number of rainy days
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
| 5 | 5 | 7 | 10 | 15 | 14 | 14 | 14 | 15 | 15 | 13 | 10 |
Thailand weather data source: weatherspark.com
Phuket weather
Below, you will find month by month the average weather conditions in Phuket. These temperatures can also be used for other areas in the Andaman Sea, such as the Similan Islands and Koh Lanta.
Phuket average temperatures
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
| max | 29°C 84°F | 29°C 84°F | 30°C 86°F | 31°C 88°F | 31°C 88°F | 31°C 88°F | 31°C 88°F | 31°C 88°F | 31°C 88°F | 31°C 88°F | 30°C 86°F | 29°C 84°F |
| min | 26°C 79°F | 26°C 79°F | 27°C 81°F | 28°C 82°F | 28°C 82°F | 28°C 82°F | 28°C 82°F | 28°C 82°F | 28°C 82°F | 28°C 82°F | 27°C 81°F | 26°C 79°F |
Phuket average number of rainy days
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
| 4 | 3 | 11 | 10 | 15 | 16 | 16 | 15 | 17 | 18 | 12 | 9 |
Phuket weather data source: weatherspark.com
Koh Tao weather
Below, you will find month by month the average weather conditions in Koh Tao. These temperatures can also be used for other areas in the Gulf of Thailand, such as Koh Samui and Koh Tao.
Koh Tao average temperatures
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
| max | 29°C 84°F | 29°C 84°F | 30°C 86°F | 31°C 88°F | 31°C 88°F | 31°C 88°F | 31°C 88°F | 31°C 88°F | 31°C 88°F | 31°C 88°F | 30°C 86°F | 29°C 84°F |
| min | 29°C 79°F | 26°C 79°F | 27°C 81°F | 28°C 82°F | 28°C 82°F | 28°C 82°F | 28°C 82°F | 28°C 82°F | 28°C 82°F | 28°C 82°F | 27°C 81°F | 26°C 79°F |
Koh Tao average number of rainy days
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
| 3 | 3 | 4 | 7 | 10 | 14 | 16 | 16 | 19 | 20 | 17 | 12 |
Koh Tao weather data source: weatherspark.com
Other factors, of course, such as the water temperature, can have an impact on when you are booking your trip to scuba dive in Thailand. In this case, it is better to check Thailand water temperatures information.