Koh Samui’s position in the Gulf of Thailand puts it on a different weather calendar from Phuket. While Phuket’s Andaman coast is in prime dry season through December, Samui’s east-facing beaches deal with the tail end of the northeast monsoon. Understanding this split determines whether December is a good choice for your trip.
The weather split: early vs late December
The Gulf of Thailand’s northeast monsoon affects the eastern shores of the peninsula and its islands from late October through December. For Koh Samui, November is the wettest month of the year. December represents an improvement — but not immediately.
Early December (December 1–15): Expect 5–8 days with rain across the month, often concentrated in this first half. Chaweng and Lamai, which face east, can see rough surf. Grey skies and passing showers are common. This isn’t a trip-ruiner for most people, but if uninterrupted beach days are essential, early December on Samui carries more risk than Phuket at the same time.
Late December (December 16–31): Conditions shift decisively. By Christmas week the skies are typically clear, humidity drops, and temperatures reach 30–31°C with light winds. NYE week is usually excellent.
The practical takeaway: if you’re arriving before December 15, consider whether Phuket or Krabi would serve your beach goals better. If you’re arriving for Christmas or NYE specifically, Samui delivers well.
Beaches in December
Bophut (north coast) is one of the best choices in early December. Facing north, it’s partly sheltered from northeast swells and tends to stay calmer than Chaweng when the monsoon tail is still active. Bophut Beach is quieter, with the low-key Fisherman’s Village strip of restaurants and bars along the beachfront.
Maenam (north coast) is the longest beach on Samui’s north shore. It’s more sheltered than Chaweng in unsettled conditions and often overlooked, making it a good option for families who want space and calm water without the full resort infrastructure of Chaweng.
Chaweng Beach is the island’s busiest and most developed stretch. In late December and NYE week, when conditions have settled, Chaweng is excellent — wide white sand, warm clear water, and the full range of beach clubs, watersports, and restaurants. This is also where the main NYE party happens.
Lamai is Chaweng’s quieter neighbour to the south. It’s a good mid-point between Bophut’s calm and Chaweng’s energy. Lamai has fewer accommodation options but some of the island’s best-value beachfront hotels.
New Year’s Eve on Koh Samui
Koh Samui’s NYE scene is centred on Chaweng. The two biggest events are:
Ark Bar Beach Resort — Runs one of the island’s most established NYE beach parties. It’s ticketed, usually priced at approximately 2,500–4,500 THB including open bar until midnight or a set period. It fills up. Buy tickets online or directly from the venue several weeks ahead.
Green Mango Club — A Chaweng Road institution, Green Mango runs a NYE club night that continues until well into the morning. Entry charges vary but the venue’s reputation means it sells out.
Most beachside hotels and resorts in Chaweng and Bophut also run private rooftop or poolside packages. These are generally 2,000–5,000 THB per person with set menus and some drinks included.
The beach itself at Chaweng has fireworks at midnight, visible from the sand without buying a ticket anywhere — though it gets very crowded.
For a broader picture of NYE options across Thailand’s beaches and Bangkok, see our New Year’s Eve in Thailand guide.
Full Moon Party proximity
Koh Phangan is 45 minutes from Koh Samui by ferry from Na Thon or Nathon Pier. The Full Moon Party runs monthly on or near the full moon at Haad Rin beach. The December full moon falls around December 14–17 depending on the year; the January full moon typically falls in the first or second week of January.
In years where the December full moon falls late (around December 28–30), there’s a rare opportunity to combine a Samui NYE with a Phangan Full Moon Party within the same trip window. Check exact lunar dates for your year before planning around this.
First-time visitors: the Full Moon Party at Haad Rin is large (20,000–30,000 people), loud, and chaotic. It’s not for everyone. In December and January it’s more crowded than quieter months. The ferry back to Samui at 06:00–08:00 the morning after is an experience in itself.
Tours from Koh Samui in December
December’s calmer Gulf waters (at least from mid-month) make it a good time for day trips around the Samui archipelago:
Ang Thong Marine National Park — The 42-island archipelago northwest of Samui is spectacular in December. Day trips include kayaking through lagoons and snorkeling. Depart from Nathon or Don Sak Pier.
Koh Phangan day trip — Beyond the Full Moon Party circuit, Koh Phangan has excellent beaches and snorkeling, particularly on the eastern and northern coasts. A quieter alternative to the party side of the island.
Samui island hopping — Combined boat trips around Samui’s offshore snorkeling spots, often including Koh Tan and Koh Mudsum for reef snorkeling.
Browse Koh Samui tours and day trips on GetYourGuide — December availability for popular day trips can be tight around Christmas and NYE; pre-booking is recommended.
Accommodation in December
Chaweng hotels book up quickly for NYE week. For the December 28–January 2 window, book 5–8 months ahead for popular beachside properties. For Christmas week, 3–4 months is generally safe.
Bophut and Maenam hotels offer slightly better value than Chaweng for equivalent quality. They’re also a more practical base if you’re visiting in early December and want the more sheltered north coast beaches.
See current hotel availability on Koh Samui at Booking.com.
December in summary
Samui in December is a tale of two halves. The first two weeks carry weather risk that makes Phuket or Krabi a more reliable choice if beaches are the priority. From December 20 onward — and especially for Christmas and NYE week — Samui is excellent: good weather, strong party scene, Full Moon Party accessible nearby, and the island running at full capacity.
For the broader picture of Thailand’s weather and what each region is doing in December, our Koh Samui travel guide covers the island year-round.