Thailand Weather in December: Temps, Rain, Where to Go
Thailand weather in December is one of the most reliable in Southeast Asia: the monsoon shifts bring drier air, long sunny spells, and comfortable temperatures. Travelers find excellent conditions across cities, mountains, and beaches, with only a few regions still seeing short showers. It is also peak holiday season, so planning ahead helps you make the most of the sunshine. Below, see how temperatures, rainfall, and sea conditions vary by region, and where to go for the best weather.
Thailand in December at a glance
December marks the transition to the most settled stretch of the year across much of the country. Humidity drops, the sky brightens, and outdoor activities are pleasant from morning to evening. The exception is the Gulf of Thailand, where early-month showers are still common before conditions improve toward New Year.
For first-time visitors, it helps to think of four broad regions. The North (Chiang Mai, Chiang Rai) covers mountains and valleys with the biggest day-night temperature swings. Central Thailand (Bangkok, Ayutthaya, Pattaya) is mainly lowland plains and large cities. The Andaman Coast (Phuket, Krabi, Khao Lak, Phi Phi) faces the Indian Ocean and is typically calm and clear in December. The Gulf of Thailand (Koh Samui, Koh Phangan, Koh Tao) faces a different seasonal wind pattern and can be showery earlier in the month before conditions improve toward New Year. Year-to-year weather can vary due to natural climate variability, so use these patterns as a guide rather than a guarantee.
Quick facts (temperatures, rainfall, sunshine)
December is generally dry and sunny with lower humidity across most regions. The Andaman side benefits from calmer seas and clearer skies as its wet season ends, while the Gulf islands transition from their late-year monsoon to more stable weather by late month. In the North and Central regions, crisp mornings and comfortable afternoons are the norm, especially away from dense urban cores.
Typical daytime highs range about 24–32°C (75–90°F). Nights in the North can drop near 15°C (59°F), and even lower at higher elevations. Rainy days are few in most places: Andaman beaches see around 6–8 brief showers in the month, Bangkok and the North often have 0–1 rainy days, and the Gulf may record around 14–15 short, intense showers early in December. Sea temperatures hover near 27.5–29°C (81–84°F), comfortable for long swims without thermal layers.
- Regions at a glance: North (mountains), Central (cities/plains), Andaman (Phuket/Krabi west coast), Gulf (Samui/Phangan/Tao east coast).
- Typical highs: 24–32°C (75–90°F); coolest evenings in the North and highlands.
- Rainy days: Andaman ~6–8; Gulf ~14–15 early month; Bangkok/North ~0–1.
- Sea temperatures: about 27.5–29°C (81–84°F) on both coasts.
- Expect long sunny spells and lower humidity versus the wet season.
- Weather can vary year to year; check local forecasts before you travel.
Where to go for the best weather
Phuket, Krabi, Khao Lak, and nearby islands typically enjoy calm seas, warm water, and excellent visibility for snorkeling and diving. In the North, Chiang Mai and Chiang Rai are cool and dry with clear mornings, making December ideal for hiking, cycling, and cultural visits. Central Thailand, including Bangkok and Ayutthaya, is comfortable for sightseeing with minimal rain and slightly cooler nights.
The Gulf islands can be a great choice later in the month. If you plan to travel in early December, choose Andaman bases such as Phuket or Krabi for more reliable sunshine, and consider the Gulf for a few days at the end of your trip as conditions improve. For example, a 10-day itinerary starting 5 December might prioritize Phuket and Khao Lak, while a trip starting 24 December could split time between Chiang Mai and Koh Samui once showers ease. This early-versus-late timing helps you balance beach time with on-land activities.
Regional weather breakdown
Regional patterns hinge on topography and seasonal winds. Northern Thailand’s elevation brings cooler nights and the biggest day-to-night range. Central Thailand’s lowlands warm up more by midafternoon, especially in cities that retain heat. The Andaman Coast benefits from calmer west-side seas in December, while the Gulf islands can see short-lived showers earlier in the month before the pattern stabilizes. The sections below highlight what to expect and how to plan activities in each area.
Northern Thailand (Chiang Mai, Chiang Rai)
Days are comfortable around ~28°C (82°F), while nights cool to ~15°C (59°F). Rainfall is very low (around 20 mm in the month) with about one rainy day on average. Higher points such as Doi Inthanon, Doi Suthep, and mountain villages can feel notably colder at dawn, especially when the wind is up, so plan for crisp mornings and clear, bright afternoons.
December is excellent for trekking, cycling, temple visits, and markets. The region’s smoke season typically starts much later in the year, so air quality is often good in December. Pack a light jacket for evenings and early excursions, and consider gloves or a beanie if you will visit viewpoints before sunrise at high elevation. Trails are usually dry, but footwear with good grip is still useful on shaded or leaf-covered paths.
Central Thailand (Bangkok, Ayutthaya, Pattaya)
Bangkok ranges about ~26–32°C (79–90°F) by day and around ~21°C (70°F) at night. Humidity is lower than in the wet months, which makes walking tours and river ferries more enjoyable. Urban heat islands can make midafternoons feel a few degrees warmer, particularly on paved surfaces and in dense neighborhoods, so plan your longest outdoor stretches in the morning or late afternoon.
Coastal towns like Pattaya are breezy with generally calm nearshore waters in December, which suits casual swims and family beaches. For midday comfort, use simple heat-management habits: seek shade during peak sun, hydrate often, pause in air-conditioned museums or malls, and wear breathable fabrics. Ayutthaya’s open archaeological sites are pleasant this month; start early to enjoy cooler temperatures and softer light.
Andaman Coast (Phuket, Krabi, Phi Phi, Khao Lak)
Expect air temperatures around ~24–31°C (75–88°F) with about 6–8 brief showers during the month. The seas are typically calm, and water temperatures average about 27.5–29.1°C (81–84°F). Beach conditions can vary with orientation: west-facing open beaches may have more exposure on breezier days, while sheltered bays and coves are calmer and clearer, especially useful for families and less-confident swimmers.
Underwater visibility often peaks in December, supporting snorkeling cruises and dive trips. Popular bases include Phuket for its range of beaches and amenities, Krabi and Phi Phi for island scenery, and Khao Lak for easy access to offshore marine parks.
Gulf of Thailand (Koh Samui, Koh Phangan, Koh Tao)
Air temperatures hover around ~24–29°C (75–84°F). Early December can bring roughly 14–15 rainy days, but showers are typically short, often 30–60 minutes, and conditions improve through the month. Seas may be choppy at times, and ferry schedules can adjust with weather, so leave buffer time for transfers.
During brief shower periods, cultural and indoor activities are easy to slot in: explore temples like Wat Plai Laem and Wat Phra Yai on Samui, try a cooking class, visit Fisherman’s Village walking street, schedule a spa session, or sample local cafes and night markets. By late December, rainfall usually eases, visibility improves, and water-based trips to Ang Thong Marine Park become more reliable.
Temperatures, rainfall, and sunshine patterns
December brings comfortable temperatures nationwide, with the widest day-night swing in the North and more steady warmth in coastal areas. Urban cores such as Bangkok can feel hotter in midafternoon due to retained heat, while coastal breezes keep perceived temperatures lower along the Andaman and Gulf shores. Sunshine hours are generous in most regions, and rainfall generally takes the form of short showers rather than long, soaking rain.
The compact overview below compares typical December conditions. Values are representative ranges; local microclimates and year-to-year variability mean actual conditions can differ. Always check location-specific forecasts during your travel week.
| Region | Day/Night (°C/°F) | Rainy days | Rainfall | Sea temp (°C/°F) |
|---|---|---|---|---|
| North (Chiang Mai) | ~28 / ~15 (82 / 59) | ~1 | ~20 mm | — |
| Central (Bangkok) | ~26–32 / ~21 (79–90 / 70) | 0–1 | Low | — |
| Andaman (Phuket/Krabi) | ~24–31 (75–88) | ~6–8 | Low–moderate | ~27.5–29 (81–84) |
| Gulf (Samui) | ~24–29 (75–84) | ~14–15 early | Moderate early | ~27.5–29 (81–84) |
Day/night temperatures by region (°C/°F)
In December, the North averages about ~28°C (82°F) by day and ~15°C (59°F) at night, with cooler readings in highland areas. Central Thailand, including Bangkok, typically sits around ~26–32°C (79–90°F) in the daytime and ~21°C (70°F) overnight. On the Andaman side, expect ~24–31°C (75–88°F), while the Gulf averages about ~24–29°C (75–84°F) with smaller diurnal swings along the coast.
Urban heat islands like Bangkok can feel a few degrees warmer in the afternoons, especially in low-wind conditions. Nighttime cooling is most pronounced in the North and at higher elevations, where crisp mornings are common. Presenting temperatures in both °C and °F helps with planning: pack for warm days everywhere and add layers for the North and mountain sunrises.
Rainfall and rainy days
The North and Central regions are very dry, often seeing 0–1 rainy days in December. The Andaman coast experiences a handful of brief showers on about 6–8 days as the wet season retreats. The Gulf side has the highest chance of showers in early December, around 14–15 days with short, intense bursts that typically clear within an hour. All-day rain is uncommon compared with the wet season.
Because showers are localized, conditions can vary between nearby beaches and neighborhoods. For smooth planning, check short-range forecasts 3–5 days before travel and again each morning. A compact umbrella or light rain shell covers most brief downpours, and flexible scheduling lets you swap beach time and indoor activities as needed.
Sunshine hours and visibility
Expect long sunny spells across much of Thailand in December, often 7–9 hours of sunshine in many regions. Morning air clarity is best in the North, and lower humidity compared with the wet season improves views and comfort countrywide. In Bangkok, occasional urban haze can soften skyline vistas, but overall visibility is much better than during rainy months.
Marine visibility is a highlight. The Andaman side commonly delivers 15–30 m underwater visibility in settled conditions, supporting snorkeling and diving. The Gulf can be lower early in the month, around 5–15 m on average, then improving to roughly 10–20 m by late December. These ranges vary with wind, tides, rainfall, and site exposure, so consult local operators for day-by-day recommendations.
Sea conditions and water temperatures
Seasonal winds reverse around this time of year, leaving the Andaman side calmer and clearer, while the Gulf gradually settles after early-month showers. Water temperatures on both coasts remain warm and inviting, and most swimmers do not need thermal protection. Safety still matters, especially on exposed beaches or during short-lived squalls.
Andaman vs Gulf: where seas are calmer
The Andaman coast is usually calmer in December due to prevailing wind patterns. Sheltered bays around Phuket, Krabi, Phi Phi, and Khao Lak often have gentle waves and clear water, ideal for families and beginner snorkelers. While rip currents are less frequent than in the wet season, they can still occur on exposed shores, so choose beaches with lifeguards when possible.
The Gulf can be unsettled early in the month, with choppier seas and occasional ferry adjustments. Conditions typically stabilize by late December. Wherever you swim, follow local beach flag systems and lifeguard advice: green generally indicates safer conditions, yellow calls for caution, and red warns against entering the water. If in doubt, opt for leeward beaches or protected coves.
Average sea temperatures (°C/°F) and snorkeling/diving notes
Sea temperatures average about 27.5–29°C (81–84°F) on both coasts in December, which is comfortable for extended swims. A rash guard or a thin 1–3 mm wetsuit adds sun and jelly protection for long sessions. High demand means dive trips and courses sell out quickly this month, so reserve in advance if specific dates or sites are important to you.
Motion sickness remedies help on ferries during choppy spells, and a protective case or waterproof pouch safeguards electronics. On the Gulf side, a compact umbrella or poncho is handy for brief showers between activities.
What to pack for December in Thailand
Packing for December is about staying cool in the daytime, adding layers for northern nights and high elevations, and being ready for short showers on the Gulf side. Lightweight, breathable clothing works almost everywhere, with modest options for temple visits and quick-drying pieces for beach days and boat trips.
City and cultural visits
Choose lightweight, breathable clothing such as cotton, linen blends, or moisture-wicking fabrics. Add a wide-brim sunhat, UV-rated sunglasses, and high-SPF sunscreen. Comfortable walking shoes or sturdy sandals, a small daypack, and a reusable water bottle support full sightseeing days.
Evenings and indoor spaces can feel cool due to air conditioning, so bring a light layer or thin sweater. Keep a compact umbrella for occasional showers, especially if you will visit the Gulf islands. Simple sun safety—shade, hydration, and periodic indoor breaks—goes a long way to sustain energy in Bangkok and other cities.
Trekking and northern mountains
For mountain mornings and evenings that can dip to about 10–15°C (50–59°F) in higher areas, plan a layering system: a breathable base, a lightweight insulating midlayer, and a compact wind or rain shell. Altitude and wind increase the chill, particularly on viewpoints like Doi Inthanon and open ridgelines, so pack accordingly. Sturdy footwear with grip is useful on uneven or leaf-strewn trails, even in dry weather.
Carry insect repellent, a headlamp, quick-dry socks, and a lightweight insulating layer for dawn wildlife walks or sunrise viewpoints. Weather can change quickly in the hills; follow park rules, stay on marked trails, and consider local guides on longer routes for safety and cultural context.
Beaches and water activities
For beach days, bring swimwear, a long-sleeve rash guard, and reef-safe sunscreen. Look for mineral formulas with non-nano zinc oxide or non-nano titanium dioxide, and avoid ingredients such as oxybenzone and octinoxate. Add a sun-protective hat and polarized sunglasses for glare on the water.
Trip planning in peak season (costs, crowds, booking tips)
December is peak season across Thailand, with higher rates and tighter availability, especially around Christmas and New Year. Booking key elements early gives you better choices for location and price. Flexible dates and a willingness to mix regions can help you track the month’s best weather while managing costs.
Budget ranges and when to book
Plan to book flights and hotels 6–10 weeks in advance, and earlier if your stay falls between 24–31 December. Many beach resorts add holiday surcharges and minimum-stay requirements. If you can, keep dates flexible to unlock better rates or alternate room types. Consider refundable or changeable bookings and purchase travel insurance in a timely manner for added flexibility around weather or scheduling changes.
Monitor fares, compare nearby airports when feasible, and weigh location versus price—sometimes a base slightly inland offers savings with easy beach or city access.
Popular tours and activities to reserve early
On the Andaman side, space is limited on Similan and Surin liveaboards, as well as on small-group day trips to Phi Phi and Phang Nga Bay. In the Gulf, Ang Thong Marine Park tours and snorkeling excursions become more reliable later in the month, and New Year events can book out dining and sunset cruises.
In the North and Central regions, reserve ethical elephant experiences, cooking classes, and river cruises ahead of time. For animal encounters, avoid riding, look for clear welfare standards, small group sizes, and transparent operations; review policies and independent feedback from reputable sources. Early reservations also help align activities with the best weather windows during your specific travel week.
Frequently Asked Questions
Is December a good time to visit Thailand?
Yes, December is one of the best months to visit Thailand. Most regions are dry, sunny, and comfortable, with low humidity. Andaman beaches have calm seas and excellent visibility. Expect peak-season crowds and higher prices, so book early.
Does it rain in Thailand in December?
Rainfall is low nationwide in December. Bangkok and the north are very dry (often 0–1 rainy days), the Andaman sees a few brief showers, and the Gulf (Koh Samui) has more short showers in early December that ease later.
How hot is Bangkok in December?
Bangkok typically ranges from about 26–32°C (79–90°F) by day and around 21°C (70°F) at night. Humidity is lower than other seasons, making city sightseeing more comfortable.
Can you swim in Phuket in December?
Yes, swimming conditions in Phuket are excellent in December. Seas are usually calm with water around 27.5–29°C (81–84°F), and visibility is good for snorkeling and diving.
Is Koh Samui rainy in December?
Conditions improve toward late December and New Year.
What is the sea temperature in Thailand in December?
Sea temperatures are typically 27.5–29°C (81–84°F) on the Andaman side and similarly warm in the Gulf. Water is comfortable for long swims without thermal layers.
What should I wear in Thailand in December?
Wear lightweight, breathable clothing, sun protection, and comfortable walking shoes. Pack a light layer for cool northern mornings/evenings and a compact rain jacket for the Gulf islands.
Which side is better in December, Andaman (Phuket) or Gulf (Koh Samui)?
The Andaman side (Phuket, Krabi) generally offers more reliable sun and calmer seas in December. The Gulf (Koh Samui) improves through the month but has more brief showers, especially early December.
Conclusion and next steps
December in Thailand brings bright skies, warm seas, and comfortable city and mountain conditions. The Andaman coast is the most reliable for beaches, the North is cool and dry, and the Gulf improves toward late month. Pack light, add layers for northern nights, and plan key bookings early to align with this peak season. Checking local forecasts close to your travel dates helps you fine-tune day-by-day activities.
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