Thailand in December is the trip most guides call perfect, and for most of the country they’re right: dry skies, the coolest nights of the year and calm seas on the west coast. But December has one wet corner that catches people out every year, and two weeks that cost far more than the rest. This guide gives you the verdict region by region, the coast to pick, the week to book and two routes that work, so you can plan the trip once and get it right.
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✅ Key takeaways
- ✓Go to the Andaman coast for beaches in December: Phuket averages about 82 mm of rain over 8 days, Koh Samui about 263 mm over 12.
- ✓Bangkok has its driest, least humid weeks of the year in December, with nights around 23 °C.
- ✓Pack a warm layer for the north: Chiang Mai mornings average about 17 °C, and Doi Inthanon can approach freezing at dawn.
- ✓Travel in the first half of December if you can: same weather, lower prices than the Christmas and New Year weeks.
- ✓If your dates fall between 20 December and early January, book flights and island rooms about three months ahead and read the resort’s gala-dinner rules.
Thailand in December at a Glance: The Verdict by Region
This section gives you the one table you need: what each region is like in December and whether to go. The figures are long-term averages from Visit Thailand Today’s December guide, based on 30-year climate normals, so a single December can run a little wetter or warmer.
The headline is simple. Three of Thailand’s four big travel regions are at or near their best. The fourth, the Gulf islands, is the one most people mix up with the rest, because it sits on the “wrong” side of the country for December weather.
| Region | Day / night | Rain | Sea | Crowds | Price | Verdict |
|---|---|---|---|---|---|---|
| Bangkok | 32 °C / 23 °C | 12 mm · 1 day | — | High | High | ✅ Go |
| Chiang Mai & the north | 29 °C / 17 °C | 14 mm · 1 day | — | High | High | ✅ Go (pack a jacket) |
| Phuket & the Andaman coast | 32 °C / 25 °C | 82 mm · 8 days | 29 °C | Very high | Very high | ✅ Go |
| Koh Samui & the Gulf islands | 29 °C / 24 °C | 263 mm · 12 days | 28 °C | Medium | Medium–high | ⚠️ Go with caveats |
If you’re weighing Thailand against other winter-sun trips, our guide to warm-weather escapes for December compares it with the Caribbean, the Canaries and the Middle East.
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Why Phuket Beats Koh Samui in December (and When It Doesn’t)
This section explains the single most important choice for a December beach trip: which coast. Thailand’s two coasts get their rain at different times of year. The Andaman coast in the west is wet from about May to October and dry from December. The Gulf islands in the east get their rain later, and their wet season runs from about October to December.
So in December the two coasts are almost mirror images. Here’s how to decide.
| If you want… | Pick | Why |
|---|---|---|
| The safest beach weather | Phuket, Krabi, Khao Lak, Koh Lanta | Dry season, calm seas, short showers at most |
| Diving and snorkelling | Khao Lak for the Similan Islands | Marine park open from 15 October to 15 May |
| Fewer crowds and lower prices | Koh Samui in the second half of December | Rain easing, rates below the Andaman side |
| Christmas or New Year on a beach | Andaman coast, booked early | Most reliable weather on the key dates |
| A party island | Koh Phangan | Big events around 24 and 31 December, weather permitting |
The Andaman coast: calm seas and open marine parks
From Phuket down to Krabi and Koh Lanta, December is high season. The sea is about 29 °C, calm enough for long swims and boat trips, and rain usually comes as a short shower that passes in an hour. Krabi’s limestone cliffs, Railay’s beaches and the islands of Phang Nga Bay are all at their most reliable in December. If you base yourself in Krabi, our guide to things to do in Krabi Town covers the evenings.
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For divers, December is one of the reasons to pick the west. The Similan Islands, a marine national park off Khao Lak, are open from 15 October to 15 May and calmest from December to March. Outside those dates the park is closed, so this is a season-only trip.
The Gulf islands: the one wet corner of December
Koh Samui, Koh Phangan and Koh Tao are still in their rainy season in December. On long-term averages, Koh Samui gets around 263 mm of rain over about 12 days in December, more than three times Phuket’s total. It’s also the windiest time of year on Samui, which can make boat trips rough.
The good news: the rain usually eases as the month goes on, so the second half of December is a much better bet than the first. If you love the Gulf islands, aim for the last ten days of December, or wait until January and February, when they are at their best.
When to Go: Thailand
Picking the right coast is the hardest part of a Thai trip, and it changes every month. This 115-page guide goes month by month and region by region: rain, sea, crowds and price for Bangkok, the north, the Andaman coast and the Gulf islands, plus the best weeks for each kind of trip.
See When to Go: Thailand →Bangkok and the North: Thailand in December’s Coolest, Clearest Weeks
This section covers the cities and the mountains, which are at their most comfortable in December. December is Thailand’s “cool season”. For Thais that means a jacket in the evening; for you it means the city is finally pleasant to walk in.
Bangkok’s driest month
December is Bangkok’s driest and least humid month, with the coolest nights the city gets: about 32 °C by day and 23 °C at night, with around 12 mm of rain. That changes how you can plan. You can walk between the Grand Palace, Wat Pho and Wat Arun in the morning without wilting, take a river boat at sunset and eat at outdoor markets in the evening.
The end of the year is lively, too. The Tourism Authority of Thailand highlights New Year countdowns at the big riverside malls and light shows along the Chao Phraya, so book a river-view room early if you want to watch from your window.
Chiang Mai, Pai and Doi Inthanon: pack a jacket
In the north, December brings clear, dry days and genuinely cold mornings. Chiang Mai averages about 29 °C by day and 17 °C at night, and at the top of Doi Inthanon, Thailand’s highest mountain, dawn can approach freezing. Mist fills the valleys in the morning and burns off by mid-morning.
December is the best time for trekking, hill-temple views and the mountain loop to Pai, which is cool and green. It’s also busy, so book northern guesthouses and the popular sunrise tours early.
Pack for a December trip that covers north and south
- ☐ A fleece or light down jacket for northern mornings and night buses.
- ☐ A light rain jacket if any part of your trip is on the Gulf islands.
- ☐ Reef-safe sunscreen and a hat for the Andaman coast.
- ☐ Clothes that cover shoulders and knees for temples and the Grand Palace.
- ☐ A dry bag for longtail and speedboat trips.
The Christmas Price Spike: What December Really Costs and How to Beat It
This section shows you the most expensive dates of the Thai year and how to work around them. December is high season everywhere except the Gulf, but two weeks stand out. From roughly 20 December to the first days of January, hotel rates over those dates reportedly run 30–50% above the rest of the season, and the islands fill up.
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Many island resorts also set minimum stays over Christmas and New Year, and some add compulsory gala dinners on 24 and 31 December. Those extras often aren’t obvious until you get to the final booking page.
20 Dec–early Jan
the most crowded and expensive weeks of the Thai year
30–50%
reported hotel premium over those dates
~3 months
how far ahead to book for those dates
1–19 Dec
the same weather, usually for less
Choose your half of the month
If your dates are flexible, travel between 1 and 19 December. The weather is almost identical, and rooms and flights are usually cheaper.
Book flights and islands first
For Christmas and New Year, lock in long-haul flights and island rooms about three months ahead. Bangkok hotels can wait a little longer.
Read the holiday small print
Before you pay, check minimum stays and whether a gala dinner on 24 or 31 December is compulsory, and what it costs.
Split your stay
Spend the most expensive nights in Bangkok or the north, where holiday premiums are usually smaller, and move to the beach after New Year.
Plan for delays
Holiday flights fill to the last seat. Our guide to handling December flight delays covers what to do if a connection goes wrong.
If you’re combining Thailand with neighbouring countries on a tighter budget, our guide to Southeast Asia in December on a budget shows which side of each country is dry and where your money goes further. Travelling from Europe? A stopover on the way, such as Dubai in December, can break up the journey.
Getting Around Thailand in December Without Losing a Day
This section covers transport, because December’s crowds affect it more than the weather does. Domestic flights, overnight trains and island ferries are all busier than usual, and the cheapest seats go first.
| Leg | Best option in December | Book how far ahead |
|---|---|---|
| Bangkok to Chiang Mai | Short domestic flight, or the overnight sleeper train for the experience | Several weeks; sleeper berths sell out over holidays |
| Chiang Mai to Phuket or Krabi | Direct domestic flight where available | As soon as your route is fixed |
| Phuket to Krabi, Phi Phi or Koh Lanta | Ferry or speedboat; calm seas in December | A few days, more around Christmas |
| Samui, Phangan and Tao | Ferry or speedboat, weather permitting | Keep flexible; cancellations happen early in the month |
Within cities, ride-hailing apps work well in Bangkok, Chiang Mai and Phuket, and river boats are the most pleasant way to move between Bangkok’s riverside temples. On the islands, book transfers through your hotel for late-night arrivals, when public options thin out.
Festivals and Holidays in Thailand in December
This section lists the dates that affect your trip, either because something is on or because the country takes the day off. Fixed public holidays don’t move; event dates do, so treat those as “usually”.
| Date | What happens | What it means for you |
|---|---|---|
| Late November to early December | River Kwai Bridge Week, Kanchanaburi | Light-and-sound shows; Kanchanaburi rooms fill |
| 5 December | National Father’s Day, a public holiday | Busy domestic travel; some offices closed |
| Usually early December | King’s Cup Regatta, Phuket | Sailing week; busier around Kata and Phuket’s marinas |
| 10 December | Constitution Day, a public holiday | Long weekends when it falls near a weekend |
| 24 and 31 December | Big beach parties, including on Koh Phangan | Island boats and rooms book out |
| 31 December | New Year’s Eve, a public holiday | Fireworks along the river in Bangkok; peak prices |
Christmas itself isn’t a public holiday in Thailand, but hotels and malls in Bangkok and the resort areas decorate and hold events. For more ideas on where to spend the last night of the year, see our guide to where to spend New Year’s Eve.
Two Routes for Thailand in December
This section gives you two ready-made plans built around December’s weather. Both start and end in Bangkok and both avoid the Gulf islands in the wettest part of the month.
Route 1: north and Andaman in 10 days
Days 1–2: Bangkok
Temples in the cool morning, a river boat at sunset, a night market in the evening.
Days 3–5: Chiang Mai
Old-city temples, a cooking class and a day trip up Doi Inthanon for sunrise. Pack the jacket.
Day 6: fly south
Fly from Chiang Mai to Krabi or Phuket. Direct flights are usually the quickest way between north and south.
Days 7–10: Krabi or Khao Lak
Beaches, a longtail trip to the islands, and from Khao Lak a day on the Similan Islands.
Route 2: beach only in 7 days
Fly straight to Phuket or Krabi and split the week: three nights in one base (Krabi’s Ao Nang or Railay, or Khao Lak for diving), then four nights on Koh Lanta for quieter beaches and long sunsets. In the last days of December, you could swap the second base for Koh Samui as its rain eases, but keep a night in hand for ferry delays.
In December, the coast you choose matters more than the hotel you book. West for sun, east only late in the month.
When NOT to Go, and the Better Month If You Want X
This section is the honest part. December is excellent for most trips, but it isn’t the best time for everyone. You can also check whether your month is a bad one with our free tool, or read the When NOT to go hub.
| If you want… | December is… | Better month |
|---|---|---|
| A sunny Koh Samui, Koh Phangan or Koh Tao beach trip | Often wet early in the month | February to April |
| Thailand at the lowest prices | Peak season, especially 20 Dec–early Jan | May, June or September (with rain) |
| Loy Krathong and the lantern festivals | A few weeks too late | November |
| Quiet Andaman beaches with good weather | Very busy | Early December or March |
| Cold weather and winter scenery | The wrong country | Try Japan in December |
If you can only travel in November, our guide to where to go in Southeast Asia in November shows which parts of the region are already dry.
Common Mistakes People Make in Thailand in December
This section covers the errors that even people who have been to Thailand before still make in December.
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Six printable timing tools for any trip: the Trip Timing Planner, When to Book, When NOT to Go, the Shoulder Season Playbook, the family timing guide and the Packing by Season System.
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1. Treating “Thailand in December” as one weather zone
Most December advice is written for the Andaman coast and Bangkok. If you book Koh Samui for the first week of December because “December is dry season”, you may get grey skies and rough boats. Check the coast, not just the country.
2. Booking Christmas week at the last minute
Leaving island rooms until November for dates around Christmas usually means paying the top of the 30–50% premium, or taking what’s left. Book about three months ahead, or move your trip into the first half of December.
3. Packing only for heat
Night buses, air-conditioned trains and northern mornings are cold in December. One warm layer weighs little and saves an uncomfortable night.
4. Ignoring the gala-dinner rules
A resort that looks reasonable for 24 or 31 December can add a compulsory dinner at checkout. Read the terms before you pay, not after.
5. Planning a same-day connection from an island
Boats run late and get cancelled in wind, especially on the Gulf side. Spend your last night near the airport you fly from, particularly if you have a long-haul connection.
Thailand in December: FAQ
The Bottom Line
Thailand in December is excellent if you pick the dry side: Bangkok, the north and the Andaman coast, ideally in the first half of the month. Decide your coast first, then lock in flights and rooms before the holiday weeks fill. For the full picture, browse our December travel guides and the Thailand guides.
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