Weather and Climate in Thailand: Seasons Month by Month and Region by Region

First, a quick note so as not to waste your time: this page provides information on the climate—that is, the patterns that repeat every year and help you choose your dates. It does not provide forecasts for the coming days. If that’s what you’re looking for, the two official services are listed at the bottom of the page.

Thailand has three seasons across most of its territory: cool and dry from November to February, hot from March to May, and rainy from May to October. But the east coast of the Gulf follows a different pattern, and that is the most useful piece of information on this entire page: when it rains on one coast, the other is often dry. November is a perfect example of this.

The three seasons, across most of the country

Average temperatures vary little throughout the year, rangingfrom 26 to 35 degrees depending on the season and region. The factor that determines whether to take a trip is therefore not the temperature, but rather the rain—and, to a lesser extent, the humidity—which makes two days at 30 degrees feel very different from one another.

The difference between the two measurements, and why it matters

There are two monsoons. The southwest monsoon, from May to October, brings rain to the Andaman coast and most of the country. The northeast monsoon, from November to February, brings dry air to most of the country, butit picks up moisture as it crosses the gulf and releases it on its western coast—the coast of Koh Samui.

Keep the last line in mind. November is the rainiest month in Koh Samui and one of the best months in Phuket, three hundred kilometers away. A November trip booked on the wrong coast is nothing like the same trip on the other. You can make your choice on the Thailand Islands page.

Two Regional Characteristics You Should Know About

The North and the Slash-and-Burn Season

From February to April, air quality deteriorates significantly throughout the north due to slash-and-burn farming. The terrain traps the smoke, and visibility decreases. This isn’t a matter of rain; it doesn’t appear on any temperature chart, and yet it is the only serious drawback in the region. Details can be found on theNorthern Thailand page.

April, the warmest month

April marks the peak of the hot season, especially in Bangkok and the inland plains. It is also the month of the upcoming Songkran, the Thai New Year, whose water fights make perfect sense once you’ve spent a day outdoors during this time of year.

What the Monsoon Really Is

The term “rainy season” conjures up images of continuous rain. That’s not what happens: it’s usually a series ofshort, heavy downpours in the late afternoon, followed by clear skies. There are days when the weather ruins your plans, but they’re the exception.

Traveling during this time has real advantages—low prices and empty tourist sites—as well as tangible drawbacks—suspended ferry service and rough seas. This topic has its own page: the rainy season in Thailand.

Choose a month

If you're looking for recommendations rather than facts, the"When to Visit Thailand" page breaks down the options by month and category, depending on what you want to do on your trip.

In summary

Three seasons: cool and dry from November through February, hot from March through May, and rainy from May through October. Temperatures vary little, ranging from 26 to 35 degrees, so rainfall is the sole determining factor. The Gulf Coast has a different pattern: November is the rainiest month there, while the Andaman Coast is dry. The north adds its own dry season from February to April, which doesn’t appear in any weather report. For forecasts for the coming days, the two official services are cited as sources.