Thailand in Every Season: When to Go and What to Expect

Thailand has three seasons: the cool season (Nov-Feb), the hot season (Mar-May), and the rainy season (Jun-Oct). Each region has its own micro-pattern. This is the guide to picking the right month for the right place.

The cool season (November to February) — the best time

This is when most international visitors come. The weather is the most comfortable: 20-30°C, low humidity, blue skies, no rain. The north (Chiang Mai) is genuinely cool — bring a jacket for the evenings. The beaches (Phuket, Krabi, Koh Samui) are at their best — calm water, clear skies, low humidity. Bangkok is the most comfortable it's ever going to be.

December: Peak season starts. The weather is the best. The prices are the highest. The crowds are the heaviest. Book ahead for the popular places.

January: Same as December but slightly fewer crowds after the New Year. Still peak.

February: The best month, in my opinion. Cool, dry, the crowds haven't yet peaked for the Chinese New Year. The flowers are starting to bloom in the north.

The hot season (March to May) — the burning season

The hot season in central and southern Thailand is genuinely hot (35-40°C, high humidity). The north has the additional "burning season" problem — the agricultural burning in Myanmar, Laos, and northern Thailand creates a smoke-haze that reduces visibility to 1 km and air quality to hazardous. Chiang Mai in March-April is sometimes called the "most polluted city in the world" for the air quality.

March-April: The Songkran festival (Thai New Year, April 13-15) is in this period, and the water fights are the headline. The heat is extreme. Northern Thailand has the burning season haze. The beaches are less crowded (the European winter crowd is gone).

Songkran (April 13-15): The water festival. The most fun of the Thai festivals, the most photogenic. Chiang Mai is the most famous for the water fights, Bangkok has a smaller version, the islands all have their own. The rest of the country treats it as a 3-day water fight. Bring waterproof everything.

The rainy season (June to October) — the green season

The monsoon comes to the Andaman coast first (May), the Gulf coast later (Sep). The rain is intense but usually short — 1-2 hours in the late afternoon, then sunshine. The rest of the day is dry. The air is fresh, the rice paddies are green, the waterfalls are at their best. The prices are the lowest. The crowds are the thinnest.

The trade-off: You might get wet. Some dive operators close (visibility drops). Some boat services to the islands stop. The most important trade-off is the air quality in the north (which improves in the rainy season, the burning season is over).

Best for: The cultural traveler, the slow traveler, the photographer (the green season light is the best), the budget traveler.

Region by region

Bangkok

Best: November-January. Avoid: April (the hottest month, 40°C). Acceptable: the rainy season, the air is fresher, the temples are quieter.

Chiang Mai + the North

Best: November-February (cool, dry, the flowers bloom). Avoid: March-April (the burning season). Acceptable: May-October (rain, but the burning is over and the green is best).

The Andaman coast (Phuket, Krabi, Koh Lanta, Koh Phi Phi)

Best: November-March (dry, calm). Avoid: May-October (monsoon, rough seas, some islands close). Note: this is the reverse of the Gulf coast.

The Gulf coast (Koh Samui, Koh Phangan, Koh Tao)

Best: February-September (dry). Avoid: October-December (the Gulf monsoon, the worst weather is Nov). Note: this is the reverse of the Andaman — Koh Samui is best in the summer, when the Andaman is rainy.

Isaan (the Northeast)

Best: November-February. Hot season is very hot here (40°C+). Rainy season is heavy but short rains.

Festival calendar

January: Chinese New Year (Chinatown in Bangkok).
February: Makha Bucha (Buddhist holiday, temple candles).
April 13-15: Songkran (Thai New Year, the water festival).
May: Visakha Bucha (Buddhist holiday, the most sacred).
July-August: Asalha Bucha + Khao Phansa (Buddhist Lent starts, the monks retreat for 3 months).
October: Ok Phansa (Buddhist Lent ends, the lantern festival, Yi Peng in Chiang Mai).
November: Loy Krathong (the famous lantern festival, the same night as Yi Peng in Chiang Mai).

The best months overall

For most travelers, the best months are December, January, and February. The trade-off: the prices are high, the crowds are heavy. The compromise: November (slightly less crowded) or March (slightly less crowded, but the burning season in the north).

For the diving: February-May on the Andaman, March-September on the Gulf.

For the festivals: April (Songkran) or November (Loy Krathong + Yi Peng).

For the budget traveler: June, July, August (the rainy season, the prices are 30-50% lower).