Weather in Chiang Mai Province
The weather of Northern Thailand, including the Chiang Mai Province, differs from the traditional divisions of spring, summer, autumn and winter. Instead, the region has three distinct seasons: the cool season, hot season and rainy season. Chiang Mai is known as the 'cool capital', and in comparison to the sticky, humid heat of Bangkok, the climate is far more agreeable.
Generally speaking, the weather of Northern Thailand is far more temperate than central or Southern Thailand. The area is more than 2,000kms from the equator and much closer to the Tropic of Cancer. This, coupled with its mountainous terrain and location in the Asian interior, brings cooler temperatures and less humidity.
The most popular time for visiting the Chiang Mai Province (weather wise) is the cool season, which runs from December to the end of February. It is in fact pleasantly chilly in the evenings, and if you are planning on visiting Chiang Mai Province at this time of year, it would be wise to bring all-weather gear along; particularly if you intend hiring a motorcycle to get around, or going on a mountain trek. However, don't leave out your summer clothes, as midday temperatures can climb well into the 30°C’s.
This season, which runs from April-June, is the tropical heat season. Although it can be humid, there is virtually no rain during this period.
The weather starts to warm up around early February, and by mid-March, the cooler nights of December are nothing but a pleasant memory, with daytime maximums regularly reaching 40°C.
The 'hot season haze', where a large amount of vegetation is slashed and burned back usually occurs in March. This can cause the air to be quite hazy and smoky, Doi Nok Strawberry Resort is closed during this period for the comfort of its guests.
The southwest monsoon usually arrives from India sometime between the end of May, and November. The rainy season is characterised by heavy downpours, but they tend to be sudden bursts that only last for 30 minutes or an hour or so.
However, like the “cool” season, the name “rainy season” is slightly misleading. While it certainly does rain during this season it’s more likely to consist of flash-flood afternoon downpours than a continual drizzle for days.
Although mosquitoes are more numerous during this time, the rainy season is actually a pleasant time to visit the north. The rains bring respite from the heat, and the landscape returns to its strikingly-gorgeous shade of green. Rainfall is usually heaviest in September, with an average precipitation of 250mm.
This season sees the weather improve as the rainy season approaches. This means sunny skies and afternoon storms to cool things off and it’s still pleasantly cooler than Bangkok and the South.
Cloud cover in this season cools the intensity of the heat down but you are still likely to get plenty of sunshine in between the showers. It remains relatively hot, though could be cloudy for days. Tourist numbers are less, but the experience is just as pleasant.
Many hikers, trekkers and backpackers come to the North in August, they get to see the province when it's at its lushest and still get plenty of sunshine.
With the rains, comes the prettiest times to visit Northern Thailand. At the tail end of the season, the rice fields create a patchwork of green across the landscape and although you might still see some rain, it still remains mostly sunny and as it begins to cool it becomes less humid.
This is also the best for rafting and river activities.