- ✓Thailand has three broad seasons — cool and dry (roughly Nov–Feb), hot (Mar–May) and green/rainy (May–Oct) — but the two coasts run on different rainfall calendars, so the month decides which beach, not just whether to pack a raincoat.
- ✓The single most useful month-level fact: the Andaman coast (Phuket, Krabi, Phi Phi, Lanta) is best Nov–Apr, while the Gulf islands (Samui, Phangan, Tao) are often more settled Jan–Sep, but variable — pick the coast that suits your month.
- ✓Demand often rises over cool-season holidays and Songkran; wetter months may offer lower rates, but festivals, school holidays and destination-specific seasons can reverse that pattern.
- ✓Festivals move with the lunar calendar — Songkran in April, Loy Krathong and Yi Peng in November, the Vegetarian Festival in the Sep/Oct window — so confirm the exact dates before you book flights around them.
- ✓Use this hub to find your month, then jump to that month's page for the regional weather, the coast verdict, what's on and what to avoid.
How the Thai year is shaped
Thailand doesn't have four seasons; it has three, and they don't line up with the calendar the way a European or North American year does. The Tourism Authority of Thailand frames it simply: a cool, drier winter (broadly November to February), a hot season (March to May), and a rainy or 'green' season (May to October). Temperatures across the country run from the high teens on a cool northern morning to the high thirties at the peak of the hot season.
A single national season chart is the wrong tool for planning a beach trip. The North can be cooler from November into January and smoky later in the dry season; Bangkok stays warm but has a wetter period; and the two coasts have different typical rainfall peaks. Month-level guidance narrows the options but never replaces the live forecast, air-quality reading or marine warning.
Think of the month as a filter applied to three questions: which coast has the calmer sea, where the crowds and prices sit, and what's on. Settle those, and the specific island, town or temple base follows. Each month page below answers all three for that month; this page gives you the shape of the year so you know which month to open.
The one fact that decides your month — Andaman vs Gulf
If you remember nothing else from this hub, remember this: Thailand has two beach coasts, and they are often wettest in different parts of the year. The Andaman coast in the west — Phuket, Krabi, Phi Phi, Koh Lanta, Khao Lak — is at its best in the cool, dry stretch from roughly November to April, and at its roughest and greenest from about May to October. The Gulf islands in the east — Koh Samui, Koh Phangan, Koh Tao — usually have a later rainfall peak, often more settled from around January through September, though rain and rough-sea days occur year-round, with their heaviest rain typically falling later in the year, roughly October to December.
A month can suggest a coast, not guarantee one. The Andaman is often more settled from November to April, while parts of the middle of the year can favour the Gulf before its later rainfall peak. Crossing coasts remains a full travel day, so compare current conditions and usually stay within one coast on a short trip.
Seasonality is a planning guide, not a forecast. Rain can be a short downpour or a prolonged severe-weather event, and prices are not uniformly low. Current sea state, warnings and operating ferries are the controlling details for a beach route.
Crowds, prices and the festival calendar
Demand often rises in the cool season, especially around Christmas, New Year and Chinese New Year, while Songkran creates another busy period in April. Some destinations offer lower rates or receive fewer visitors during wetter and shoulder periods, but school holidays, events and local weather patterns can produce exceptions. Compare live prices for the exact route and dates rather than assuming a nationwide low season.
The second rhythm is festivals, and most of Thailand's big ones follow the lunar calendar rather than fixed dates. Songkran, the Thai New Year water festival, lands in mid-April. Loy Krathong and Chiang Mai's Yi Peng lantern festival fall on the November full moon. The Phuket and Bangkok Vegetarian Festival follows a Sep/Oct lunar window. Chinese New Year (a flagship Bangkok and Hat Yai event) falls in late January or February. The Full Moon Party on Koh Phangan runs to the lunar month. Because these shift year to year, every date on the month pages renders as 'verify official' against the Tourism Authority of Thailand — confirm before you book flights around a festival.
The month pages below turn all of this into a single verdict each: the regional weather, the coast call, crowds and price, what's on, and who the month suits best. Find your month, open its page, and plan from there.
Sources and official planning resources
The Thai year · at a glanceMonth FC
- Cool & dry season
- Roughly Nov–Feb — the broad sweet spot; peak crowds and prices, book early
- Hot season
- Mar–May — early-temple starts and pool hotels; Songkran mid-April
- Green / rainy season
- May–Oct — lower prices, lush, fewer crowds; ferry & sea risk rises
- Andaman coast (best)
- Phuket, Krabi, Phi Phi, Lanta — roughly Nov–Apr
- Gulf islands (best)
- Samui, Phangan, Tao — often more settled Jan–Sep, but variable; heaviest rain is usually later in the year
- Best for
- Choosing your travel month, then the right region and coast for it
- Verify before booking
- Festival dates (lunar), and the current sea & ferry status for your coast
