Weather in Chiang Mai and Northern Thailand
The weather of Northern Thailand, including Chiang Mai, 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 sweaty heat of Bangkok, the climate is far more agreeable. Chiang Mai weather, month by month.
Cool season
The most popular time for visiting Chiang Mai ( 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 at this time of year, it would be wise to bring some all weather gear along. Particularly if you intend hiring a motorcycle to get around, or going on a mountain trek, pack some warm kit. However, don't leave out your summer clothes, as midday temperatures can climb well into the 30s (Celsius).
Hot season
The weather start heating up in Chiang Mai after New Year, and by mid-March, the nippy nights of February are nothing but a pleasant memory, with daytime maximums regularly reaching 40C. Try to avoid a holiday to Thailand during this time (April to June) - unless you are completely accustomed to tropical heat, you are likely to find the humidity utterly draining. Despite all the moisture in the air, however, there is virtually no rain during this period.
With the lack of water, blazing heat and slash-and-burn agricultural practices, the usually lush green jungle that covers the city's surrounding hills turns to a charred brown from fires that burn almost constantly from January until the rains arrive. Not only does this affect the vegetation, but a trademark 'hot season haze' hangs over the entire city and its surrounds, obscuring the otherwise beautiful vistas.
Rainy season
The southwest monsoon usually arrives from India at the end of May, and from then until November the weather in Chiang Mai and Northern Thailand get very, very wet. The rainy season is characterized by torrential downpours, but they tend to be sudden bursts that only last for an hour or so, rather than a steady stream of water. Although mosquitoes are rife during this time, the rainy season is otherwise 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 for that month.
Murky March health hazards
Chiang Mai and Northern Thailand has a particularly chronic problem with burning and resulting haze in March. The mountain views disappear as the Ping River valley chokes under a dusty haze that can often be a health hazard. This is the result of indiscriminate burning by ill-educated peasant farmers, couple with stagnant breeze-less weather at this time of year. Authorities have failed in recent years to tackle the issue, as tourists are advised to stay away and locals remain indoors on days when the dust particle levels far exceed accepted international health thresholds.
Generally speaking, the weather of Northern Thailand is far more temperate than central or Southern Thailand. The area is more than 2000kms 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. However there is still quite a bit of precipitation during the rainy season and the weather gets very chilly once you leave Chiang Mai and head up into the mountains.
Chiang Mai and Northern Thailand monthly weather
Chiang Mai and Northern Thailand weather in January
January is a very popular month to visit the North, as it experiences Thailand’s coolest weather, making Chiang Mai and the mountains around a novelty with Thai tourists. Expect temperatures similar to a sunny European summer day, somewhat hazy, and chilly at night.
Chiang Mai and Northern Thailand weather in February
The weather and temperatures are still very agreeable in Chiang Mai in February, though it still gets quite hot around midday in the valleys. It never rains, but by now the landscape is quite dry and the vistas hazy. Tourist services remain busy.
Chiang Mai and Northern Thailand weather in March
March is the worst time to visit Chiang Mai, weather wise, since the air is thick with dust, and micro-particles from widespread rural burning. The haze removes any view of the mountains, there’s no breeze and the results can be a health hazard (see above box) on certain days.
Chiang Mai and Northern Thailand weather in April
The weather in Chiang Mai gets very hot in April, as temperatures peak in the mid 30s celcius, the rain has yet to cool the region down and the landscape remains dry. The one reason to visit is the annual Songkran water splash festival which is best enjoyed in Chiang Mai, so hotels are full mid-month.
Chiang Mai and Northern Thailand weather in May
From May onwards the tourist season in Chiang Mai and Northern Thailand is in decline, but the weather improves as the rains arrive. This means sunny skies and afternoon storms to cool things off. Some months the rains come late.
Chiang Mai and Northern Thailand weather in June
It’s still hot in June in Chiang Mai as the weather moves into the full rainy season, bringing with it 90 per cent humidity, adding to the immense feeling of warmth. It’s still cooler than Bangkok and the South.
Chiang Mai and Northern Thailand weather in July
July is low season in Northern Thailand, cloud cover in the rainy season cools the weather in Chiang Mai but you also get plenty of sunshine in between the showers. It remains hot, though could be cloudy and warm for days. Room rates are cheaper, tourist numbers far less, but the experience just as pleasant.
Chiang Mai and Northern Thailand weather in August
Mainly backpackers come to Chiang Mai in August, while most other tourists prefer the Northern Hemisphere summer. This means the budget travellers get out-of-season deals, see the province when its most lush and still get plenty of sunshine, even if it’s humid and sometimes cloudy.
Chiang Mai and Northern Thailand weather in September
September is one of the quietest months for tourism in Chiang Mai and usually the wettest weather. Expect showers almost every day, and cloud cover but warm temperatures, a good chance of some sunshine, and high humidity. Best bargains on prices this month.
Chiang Mai and Northern Thailand weather in October
October is one of the prettiest times to visit Chiang Mai and Northern Thailand, at the tail end of the wet weather when the rice fields create a patchwork of green across the landscape. It might still rain regularly but remains mostly sunny and begins to cool and become less humid. However there are few tourists to enjoy this.
Chiang Mai and Northern Thailand weather in November
Prices jump up from November 1st as the tourist season gets going and the weather dries up, with sunny skies, cooler days and the lush remains of six months of rain. It’s one of the best times to visit, not quite busy yet but some of the best weather, with clear views of the mountains.
Chiang Mai and Northern Thailand weather in December
December is probably the busiest month for tourism in Chiang Mai and Northern Thailand as local Thai tourists make the most of the cool weather. Expect full hotels and busy roads during long weekends, especially in Pai, but nice clear mountain views, chilly evenings and sunny skies.
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