Thailand is a year-round destination, but timing matters for specific regions. The Andaman coast (Phuket, Krabi) and Gulf coast (Koh Samui) have OPPOSITE rainy seasons, so you can always find sun somewhere.
Quick Answer
Overall best: November-February (cool, dry). Budget: June-September (30-50% off). Festivals: Songkran (Apr), Loy Krathong (Nov). Diving: February-May (clearest water).
Month-by-Month Guide
January
💡 Peak season. Best weather everywhere. Highest prices. Book ahead.
February
💡 Driest month. Perfect for islands, beaches, and Chiang Mai. Chinese New Year celebrations.
March
💡 Getting hot. Last month before rains. Great diving visibility. Burning season haze in north.
April
💡 HOTTEST month. Songkran (Apr 13-15) is unmissable. Rains begin late month.
May
💡 Green season starts. Prices drop 30%. Fewer tourists. Short afternoon rains.
June
💡 Good value. Gulf islands still dry. Bangkok rain is brief. Good for Koh Samui.
July
💡 Monsoon but manageable. Great for Koh Samui, Koh Tao. Cheapest flights.
August
💡 Wettest period for Andaman coast. Gulf islands OK. Bangkok: dramatic sunsets.
September
💡 Heaviest rain month. Lowest prices. Vegetarian Festival (Phuket) late Sep.
October
💡 Rain easing. Transition month. Loy Krathong prep. Gulf islands getting wet.
November
💡 Loy Krathong and Yi Peng (Chiang Mai). Andaman islands reopen. Perfect.
December
💡 Peak season begins. Christmas/NY crowds. Beautiful weather everywhere.