When to visit

Is October considered monsoon season in Thailand?

Updated 5 June 2026

Short answer

Yes, October is still monsoon season across most of Thailand, though it's transitional. The Andaman coast (Phuket, Krabi) is in its final monsoon weeks and improving rapidly by late October. The Gulf coast (Samui, Phangan) is entering its own rainy season peak. Bangkok and the north are drying out. By the end of October, the country is moving toward high season, but you can't call October clear across the board.

Thailand's monsoon situation in October is complicated by the fact that the country has two separate monsoon systems. Understanding both is the key to making sense of October.

Two monsoons, opposite timing

The southwest monsoon affects the Andaman coast (Phuket, Krabi, Phi Phi, Koh Lanta) from roughly May to October. It drives rain from the Indian Ocean over the western coast. October is the final month of this monsoon.

The northeast monsoon affects the Gulf coast (Koh Samui, Koh Phangan, Koh Tao) from roughly October to January. It drives rain from the South China Sea over the eastern coast. October is the beginning of this monsoon.

So October is simultaneously the end of one monsoon and the start of another, affecting different coasts.

Andaman coast (Phuket, Krabi)

October is the tail end of the southwest monsoon. The rain is tapering off. Early October still sees significant rainfall (around 200mm for the month), but by late October the dry season transition is clearly underway. Phuket improves noticeably through the month.

Gulf coast (Samui, Phangan, Koh Tao)

October is when the northeast monsoon begins to make itself felt on the Gulf. Samui's worst months are October and November. Tropical depressions can move through the Gulf of Thailand at this time of year, bringing days of sustained rain. This is genuinely the worst weather period for the Gulf islands.

Bangkok

Bangkok sits between the two monsoon systems, technically on the Gulf side but sheltered enough that it has its own pattern. The rainy season in Bangkok winds down through October. Early October can still see flooding in low-lying areas during heavy storms. By mid-to-late October, Bangkok is drying out and becoming the pleasant cool-dry-season city it is from November to February.

The north (Chiang Mai)

October is late monsoon in the north. Rain is lighter than August-September. By late October, Chiang Mai is approaching its excellent November-February cool season. Waterfalls and greenery are still at their peak from the monsoon season.

What "monsoon season" means in practice

If you're booking a holiday and asking whether October is risky: yes, it has weather risk, particularly in the first half of the month and particularly on the Gulf coast. By late October, Phuket is improving and Bangkok is good. The Gulf islands (Samui especially) are genuinely best avoided in October regardless of which week.

For the full October regional breakdown, see our Thailand in October guide.