Thailand has three seasons that affect wellness travel:
November–February (Cool & Dry) — best overall. Comfortable temperatures (20–30°C), low humidity, low rain. Peak tourist season, prices higher, but ideal for outdoor classes.
March–April (Hot) — temperatures 35°C+, increasing humidity. AVOID northern Thailand (Chiang Mai, Chiang Rai, Pai) due to agricultural burning — air quality reaches hazardous levels (PM2.5 200+). Andaman beaches (Phuket, Krabi) and Koh Samui are still excellent.
May–October (Rainy) — varies by coast: - Andaman side (Phuket, Krabi): heavy rain, some shops close, but discounts. Dive season closed for Similan. - Gulf side (Koh Samui, Koh Phangan, Koh Tao): generally better in this period, drier than Andaman. Diving still excellent on Gulf.
Best months by activity: - Yoga retreats: November–February - Muay Thai: any time (indoor) - Diving Andaman: November–April - Diving Gulf: March–September - Cooking classes: any time - Spa: any time
Korean tourists peak: December and Lunar New Year (late Jan/early Feb).