When to Visit Chiang Mai

January in Chiang Mai is the coolest month of the year, with highs reaching 30°C (86°F) and lows that can drop to a brisk 15°C (60°F) after dark. Pack a light layer for evenings. Crowds are high, the sky is reliably clear, and the city is at its most comfortable for walking.

February warms up noticeably, with highs touching 32°C (91°F) and lows around 16°C (62°F), and the smoke season begins to build. Days are still largely sunny and dry, just 10mm of rainfall. But air quality starts to deteriorate toward month's end. Crowds remain high.

March is the beginning of the serious heat, with highs reaching 35°C (95°F) and overnight lows of 20°C (68°F). Smoke is often at its worst this month, and anyone sensitive to air quality will notice it. Rainfall ticks up slightly to 20mm but this is still effectively dry season. Crowd levels are medium.

April is technically the hottest month, pushing 36°C (98°F) at peak, with lows around 23°C (74°F). The Songkran water festival in mid-April turns the entire city into a cheerful street-level water fight for several days, which is either the best or worst timing depending on your temperament. Smoke is still present early in the month. Crowd levels are medium to high around Songkran, then quiet.

May marks the arrival of the monsoon, and Chiang Mai's weather shifts considerably. Highs ease back to 34°C (94°F), lows sit at 24°C (75°F), and rainfall jumps to 168mm. The smoke clears almost overnight once the rains come, and the air quality improvement is dramatic. Crowds drop to low.

June continues the wet pattern with 119mm of rain and temperatures ranging from 24°C (76°F) overnight to 33°C (91°F) in the afternoon. The rain tends to fall in concentrated afternoon bursts, leaving mornings generally workable. Crowds remain low.

July is similar, with 150mm of rainfall and highs around 32°C (89°F). The surrounding rice paddies are at their lushest, and Chiang Mai's night markets and restaurants are pleasantly uncrowded. Crowd levels stay low.

August is statistically the wettest month, with 224mm of rain, though the temperature profile is gentle, highs of 31°C (88°F) and lows of 24°C (75°F). Waterfalls in the nearby mountains peak, and Doi Inthanon National Park looks spectacular. Crowd levels are low.

September remains very wet at 208mm, with temperatures barely distinguishable from August, highs 32°C (89°F), lows 23°C (74°F). The occasional flooding in lower-lying areas can affect some roads. Crowd levels are low to medium.

October sees rainfall begin to ease to 124mm, temperatures dip slightly to a high of 31°C (89°F) and a low of 22°C (72°F), and the landscape remains intensely green. The city starts waking up again as the shoulder season approaches. Crowds are medium.

November is when Chiang Mai wakes up. Rainfall plunges to 41mm. Daytime highs hover at 30°C (87°F). Nights drop to 19°C (67°F). Loi Krathong lights the sky. Thousands of paper lanterns lift above the old city moat. The spectacle is memorable. Crowds are high.

December delivers the coolest, driest spell. Highs sit at 29°C (84°F). Lows dip to 16°C (62°F). Only 15mm of rain falls. Evenings call for a light jacket. International visitors and Thai travellers fill the lanes. Crowds are high.