Weather at Chiang Mai International Airport
Chiang Mai is often thought of as Thailand's 'cool' destination, but in truth the weather is warm and tropical throughout most of the year, and in fact the months of March and April can be uncomfortably hot. The 'cool' dry season is from December to February, and this is also the tourist high season. Starting in February, the days, and nights, will become increasingly warmer until around April, when daytime highs can easily reach 40°C / 100°F. Rains will start to fall in April and May, with the rainy season reaching its height in August and September. Note that rains typically come in heavy late afternoon thunderstorms. Mornings can be clear and sunny.
Five-Day Weather Forecast for Chiang Mai
Weather information provided by Weather Underground.