December is Thailand at full throttle. The Andaman Coast is in prime dry season, the north is cool and clear, and even the Gulf islands have recovered from their October-November monsoon. The trade-off is price: Christmas week through New Year’s is the most expensive period of the year, and popular resorts fill months in advance. Early December (1st-20th) offers nearly identical weather at significantly lower cost.
Weather by Region
Bangkok is dry, warm, and comfortable at 26-32°C. December averages fewer than 10mm of rainfall - effectively zero rain. Humidity is low by Thai standards. This is one of the best months for walking the city’s temples, markets, and canal-side neighbourhoods without the heat exhaustion that arrives from March onward.
Chiang Mai and the north are in cool season - the best weather of the year. Overnight lows reach 12-16°C in the mountains (pack a light jacket), while daytime highs sit at 27-30°C. Skies are clear and the air is fresh. December is the last month before the burning season begins in February, so visibility for mountain viewpoints and trekking is excellent.
Andaman Coast (Phuket, Krabi, Koh Phi Phi, Koh Lanta) is in peak dry season. Rain is rare, seas are calm, and all islands are fully accessible. The Similan Islands are in their prime diving window. Ferries run full schedules to every Andaman island. Beach conditions are at their absolute best - clear water, no current warnings, and reliable sunshine.
Gulf Coast (Koh Samui, Koh Phangan, Koh Tao) has emerged from its November monsoon. Early December can still see occasional showers on Koh Samui, but by mid-December conditions are dry and sunny. Koh Tao diving visibility improves steadily through the month. The Full Moon Party on Koh Phangan - the December or New Year’s Eve edition - is one of the biggest of the year.
Diving and Snorkelling
December is excellent for diving on both coasts. The Similan Islands liveaboard season is in full swing - Richelieu Rock, Koh Bon, and Koh Tachai offer encounters with manta rays and whale sharks. Visibility reaches 25-30 metres. Book liveaboards 6-8 weeks ahead for December departures as Christmas-period trips fill quickly.
Koh Tao enters its improving winter season with visibility at 15-20 metres and calm seas. The combination of good conditions and high demand means dive boat group sizes are larger than in low season - book early-morning departures for smaller groups.
Festivals and Events
HM King Bhumibol Adulyadej Memorial Day (December 5) is a national public holiday and also celebrated as Thai Father’s Day. Yellow - the late King’s colour - is worn by Thai people across the country. Government buildings and main roads are decorated with yellow bunting and royal portraits. Some businesses close, but tourist attractions generally remain open.
Constitution Day (December 10) is another public holiday, though its impact on tourism is minimal.
The New Year’s Eve countdown at CentralWorld in Bangkok is Thailand’s largest New Year celebration, drawing hundreds of thousands. Koh Phangan’s Full Moon Party either falls on or near New Year’s Eve and becomes a massive multi-day event. Phuket’s Patong Beach holds a large countdown party with fireworks. All major beach destinations have New Year’s Eve events.
Prices and Crowds
December operates on two tiers. Early December (1st-20th) is high season with good weather and manageable prices - resorts charge high-season rates but availability is reasonable. Christmas week through New Year (December 22-January 2) is the most expensive period of the year. Phuket beachfront resorts charge peak rates with minimum-stay requirements. Koh Samui and Krabi are similarly inflated. Book accommodation 2-4 months ahead for the holiday period. Bangkok is busy but pricing remains more moderate than the islands.
Flights from Europe and Australia are at their most expensive in the final two weeks of December. Domestic flights within Thailand also increase, particularly Bangkok to Phuket and Bangkok to Chiang Mai.
Which Islands to Choose in December
December is the one month when you genuinely can’t go wrong on either coast.
Andaman Coast is in full swing. Phuket has the largest resort infrastructure, the biggest New Year countdown parties, and direct flights from most European hubs. Krabi is the better base for day trips to Railay Beach and the four islands. Koh Phi Phi is worth a 2-3 night stopover - the beaches are at their clearest in December. Koh Lanta is the quieter Andaman alternative: a stretched beach road, no full-moon party scene, and a more relaxed atmosphere than Phi Phi. Koh Lipe in the far south is stunning - tiny, genuinely clear water, and surrounded by national park. It fills up over Christmas week though.
Gulf Coast is genuinely good in December. Koh Samui has dried out and is excellent by mid-December. Koh Tao diving is in excellent condition. Koh Phangan’s Full Moon Party in December - often around Christmas - is one of the biggest of the year with a strong international crowd.
Northern Thailand in December is excellent for those not chasing beaches. Chiang Mai and Pai are cool and clear. Chiang Rai’s White Temple (Wat Rong Khun) is spectacular on a crisp December morning. Doi Inthanon - Thailand’s highest peak - sees cool temperatures and clear mountain views. The north is far cheaper than the beach resorts and offers compelling mountain scenery.
Budget Estimates for December
December splits sharply between early month and the Christmas-New Year holiday period.
- Early December (1st–20th): High season but manageable. Phuket 3-star beach resort: 2,500–5,000 THB per night. Koh Samui: 2,000–4,500 THB. Chiang Mai boutique hotel: 1,500–3,000 THB.
- Christmas week to New Year (21 Dec–2 Jan): Peak pricing. Phuket beachfront resorts charge 6,000–20,000 THB per night with minimum 3–5 night stays. Koh Samui and Krabi comparable. Bangkok remains more moderate: 2,000–5,000 THB for a central 4-star.
- Flights: Peak fares from Europe and Australia. London–Bangkok in Christmas week: £700–1,000+ return. Book by October.
- Food: Street food and local restaurants remain stable at 60–120 THB per meal regardless of season. Resort restaurants and beach clubs carry 400–900 THB per dish during peak.
What to Pack for December
December is Thailand at its most comfortable - cool enough that packing is easy.
- Light summer clothing — Bangkok and coasts are warm (26–32°C) but not oppressively so
- A light jacket for the north — Chiang Mai evenings reach 12–16°C; pack a mid-layer if heading north
- Smart-casual for New Year’s Eve — beach clubs and countdown events on Phuket have dressy atmospheres; a light dress or smart shirt for the occasion
- Rash vest and reef-safe sunscreen — Andaman waters are clear and UV exposure during snorkelling is high
- Dry bag — useful for ferry crossings to islands; December seas are calm but deck spray happens
- Covered clothing for temples — shoulders and knees covered; a sarong is the lightest solution
Where to Go in Thailand in December
- Bangkok: Bangkok city guide — NYE countdown at CentralWorld
- Chiang Mai: Chiang Mai guide — cool season at its best
- Phuket: Phuket guide — prime dry season, big NYE events
- Koh Phi Phi: Koh Phi Phi guide
- Koh Lanta: Koh Lanta guide — quieter Andaman option
- Koh Lipe: Koh Lipe guide — stunning far-south island
- Koh Samui: Koh Samui guide — excellent from mid-December
- Koh Phangan: Koh Phangan guide — Full Moon Party near Christmas
- Koh Tao: Koh Tao guide — diving year-round
- Krabi: Krabi guide
Planning
See the best time to visit Thailand for a full seasonal comparison, or the Thailand budget guide for cost planning. Browse Thailand tours and day trips - book ahead in December as Similan Islands liveaboards and island day tours fill up fast over Christmas.
Plan Your Trip
December runs on two pricing tiers. Early December (1st–20th): peak-season weather at shoulder-season prices — book 3–4 weeks out and you’ll still find good availability. Christmas to New Year (Dec 22–Jan 2): the most expensive period of the year; Phuket beachfront resorts charge 6,000–20,000 THB/night with minimum stays. For Christmas week, book 2–4 months ahead. Similan Islands liveaboards from Khao Lak also fill for the holiday period — if diving is the priority, confirm your liveaboard before booking flights. For New Year’s Eve, Bangkok’s CentralWorld countdown and Koh Phangan’s Full Moon Party are the two biggest events.
- ✈️ Flights to Thailand — Christmas week: book by October
- 🛡️ Travel insurance
- 📱 Thailand SIM card or eSIM
- 🏨 Hotels in Thailand — Christmas–NYE minimum stays apply at most resorts
- 🗺️ Thailand itineraries