While the world's weather has changed and seasons are not quite as clearly defined as they once were, parts of Thailand are best visited in specific months. Rain pops up unexpectedly even in the dry season and you'll still find plenty of places to visit during the monsoon months.
Depending on where you happen to be, rain during the monsoon season can simply be a welcomed afternoon shower to cool things down or storms can rage for days, even flooding some areas. A benefit of traveling during the 'off' season is that you'll have to fight fewer crowds and can get better deals on accommodation in popular areas.
- Read about how monsoons affect the weather in Southeast Asia.
When to Visit Thailand
The dry season and busiest time in Thailand is traditionally from November until April. Temperatures in January and February are pleasantly warm but then climb to scorching hot around March and April before the monsoon begins. The monsoon rains start around May or the beginning of June.
Traveling during the monsoon season is hit or miss, however, you'll be able to enjoy some places in Thailand with little rain or only occasional thunderstorms. The north of Thailand typically receives less rain than the south during the monsoon season.
Weather in Bangkok
Bangkok is typically scorching hot throughout the year; you'll want loose-fitting clothing and open shoes such as flip-flops. Thunderstorms pop up in afternoons during the wet season, sometimes flooding the streets.
The pollution in Bangkok keeps humidity as high as possible year round.
Climate in the North
While Chiang Mai is relatively cooler and more mild than the rest of the country thanks to higher elevation, pollution from the city's traffic can trap in humidity during the hot months of March and April. Temperatures can dip into the 60s Fahrenheit at night in Chiang Mai during the wet, cooler months.
Dust and uncontrolled fires cause poor air quality in March and April around Chiang Mai and Northern Thailand. The fires are an annual event that the government has not been able to control. People with allergies to smoke or dust will be better off visiting at a different time of year.
Weather in the Thai Islands
The weather in the Thai islands is affected by more than just the time of year; storms at sea can bring rain even during the dry months.
Rain begins around April and tapers off in October on the west coast for islands in the Andaman Sea such as Koh Lanta and Phuket. The islands such as Koh Tao and Koh Phangan in the Gulf of Thailand see the most rain between October and January.
Some islands such as Koh Lanta practically close down during the monsoon season. While you'll still be able to arrange transportation there, your eating and accommodation choices will be very limited. Read about Koh Lanta weather to better understand the distinct seasons there.
Koh Chang in the Gulf of Thailand is hit hard by monsoon rain between June and September; many guesthouses close down for the season.
- See a list of popular islands in Thailand to visit.
Busy Times and Festivals in Thailand
The Christmas and New Year holidays tend to attract large crowds to Bangkok, then the busy season climbs steadily from January onward.
An unofficial busy season hits the islands in Thailand around June as many university students from Europe and Australia head out to party on islands such as Koh Tao, Koh Phangan, and Koh Phi Phi. The islands quiet down again slightly after the students finish their summer breaks.
The largest festivals in Thailand tend to make accommodation prices skyrocket and transportation fills up before and after the celebration.
Chiang Mai is the epicenter for Songkran, the Thai new year and water festival, around the middle of April. Accommodation and transportation are completely booked both before and immediately following the festival.
The Haad Rin area of Koh Phangan in the Gulf of Thailand attracts enormous crowds of revelers each month bound for the famous Full Moon Party; accommodation around Haad Rin hits maximum capacity. See a list of Full Moon Party dates to plan your visit accordingly.
The Loi Krathong and Yi Peng festivals attract huge crowds to Chiang Mai and bog down transportation. Dates change annually, however, the festival is usually around November.