December is firmly in the cool, dry high season with comfortable temperatures for beach and city travel; it is a very popular month so book early for Christmas/New Year weeks. Clear days and mild evenings make outdoor activities enjoyable.
Average daily low and high (°C) and monthly rainfall. The badge shows how it feels, allowing for humidity.
Average temperature across Thailand in December.
Chiang Mai, Chiang Rai, Golden Triangle, Pai
A return to gradual warming begins in late December, with daytime sunshine increasing while mornings may still be brisk, particularly around Chiang Rai and higher-altitude villages. Trekking trails are firm and dry, making this one of the best months for extended multi-day hikes and visiting remote hill-tribe homestays. Book ahead for New Year and year-end festivities as domestic travel spikes.
Isan: Ubon Ratchathani, Khon Kaen, Udon Thani, Nakhon Ratchasima
December keeps the northeast pleasant and largely rain-free, with crisp mornings and mild daytime warmth perfect for exploring cultural attractions and river towns. Camping on Khao Yai plateaus is popular, and night markets bustle with seasonal food; cool nights require a warmer layer. Avoid expecting beach-style warmth - the region remains a dry, open plain with notable temperature swings between day and night.
Bangkok, Ayutthaya, Kanchanaburi
December keeps cool mornings and warm days, and Bangkok hums with festive markets and a packed dining scene along the Chao Phraya. Day trips to Ayutthaya and Kanchanaburi are ideal now; bring a light sweater for air-conditioned interiors and cool nights. This is high season - book ahead and be prepared for busy transport links, especially around Christmas and New Year.
Pattaya, Hua Hin, Koh Chang, Trat coast
December sees calm seas and sunny days that draw both international tourists and Bangkok weekenders to Hua Hin and Pattaya; charter boats and diving trips operate reliably. Early-morning fishing trips and beach walks are pleasant, though some resorts raise rates for peak-season demand. Light layers for cooler nights are useful, and expect more crowded piers and longer waits for popular ferry routes.
Koh Samui, Koh Phangan, Koh Tao
December is prime season on Koh Samui and Koh Phangan: golden beaches, pleasant sea temperatures and vibrant island life with full dive schedules and regular boat services. Expect higher prices and busier piers, especially around Christmas and New Year; book early for popular accommodations. Evenings are warm but not oppressive - bring light, breathable clothing and a hat for daytime exploration.
Phuket, Krabi, Phi Phi, Khao Lak
December brings bright, dry weather, steady seas and warm daytime temperatures making it peak season for beaches, diving, and island-hopping. Expect crowds and higher prices across Phuket, Phi Phi and Khao Lak, especially around holidays; reserve transfers and snorkeling trips early. Evenings are pleasantly cool for coastal dining - pack light breathable clothes and early reservations for popular restaurants.
December features national holidays and public commemorations (dates and observances vary); tourist infrastructure is fully active during the high season.
See how December compares with the rest of the year, then read the full guide.