Chiang Mai in April: what to expect

April is the last month of the hot, dry season in northern Thailand and the hottest of the year in Chiang Mai. Afternoons commonly reach the mid-to-high 30s °C, and the heat holds until well after sunset. Rain is uncommon, though a few short showers can arrive late in the month as the monsoon edges closer.

The bigger issue is not temperature but air. The northern burning season runs roughly February to April, and Chiang Mai's air quality in this window is regularly among the worst in Asia. Some days are clear after rain or a wind shift; others are not. Check the AQI on the morning you plan to be outdoors, and treat a bad reading as a reason to change plans rather than push through.

UV is strong all month and the sun is directly overhead at midday. Plan outdoor sightseeing before 10am and after 4pm.

April splits into three parts. The first ten days are moderately busy with the tail of the cool-season crowd. Songkran week (13–15 April, with travel days either side) is the busiest and most expensive stretch of the month: hotels in the old city fill, and buses, trains and flights to and from Chiang Mai sell out. After about 18 April, demand drops sharply and rates fall with it.

If you are coming for the festival, book accommodation and onward transport several weeks ahead. If you are not, the second half of the month is the cheaper and quieter choice, at the cost of more heat and haze.

Songkran, the Thai New Year, is the month's defining event. It runs 13–15 April nationwide, with water throwing in the streets, temple visits and family gatherings. In Chiang Mai it is one of the biggest celebrations in the country, centred on the old city moat and Tha Phae Gate area. Many shops and restaurants close for part of the holiday, and alcohol sales are restricted on some days.

Expect traffic closures, soaked pedestrians and a slower city for those three days. Phones, passports and cameras need waterproof protection. Outside Songkran week, April has no major festival in Chiang Mai.

In April you want shade, water and air-conditioning rather than long hikes. Temples in the old city — Wat Phra Singh, Wat Chedi Luang, Wat Chiang Man — are walkable in the early morning and easy to retreat from at midday. Doi Suthep is cooler than the city by a few degrees, but check the AQI before heading up, since haze often sits in the valley and views can disappear.

Indoor and shaded options work better than usual: cooking classes, massage, the city's cafés and museums. If you want a day out of the city, Chiang Dao and Mae Hong Son are higher and cooler, but the same haze caveat applies. Elephant sanctuaries and jungle activities are hot, dusty work in April — start at dawn if you go.

For a cooler alternative, the Gulf islands (Ko Samui, Ko Phangan, Ko Tao) are in their dry, calm season in April, and the Andaman coast is still workable before the monsoon arrives in May.

Pack for heat and sun, not rain. Light, loose, quick-drying clothing in light colours; a hat and sunglasses; high-factor sunscreen; and a refillable water bottle, since you will drink far more than usual. Sandals or breathable shoes beat boots.

Add a mask (N95 or equivalent) if you are sensitive to smoke or plan to be outdoors on a bad air day, and a waterproof pouch for phone and passport if you are in Chiang Mai over Songkran. A light long-sleeve layer helps with strong sun and with air-conditioned interiors.

March is slightly cooler but still inside the burning season, with similar haze. May brings the first real rains and the start of the green season: hotter at the start, then gradually cleaner air as the rain washes the smoke out. June is wetter and quieter, with lower prices.

If clean air is the priority, the best window in Chiang Mai is November to February, when the cool, dry season arrives and the burning season has not yet begun.