Cambodia experiences two main seasons and December starts the cooler, dry season. Cool is relative, though, as Cambodia is a tropical country and experiences warm-to-hot temperatures year-round. Average December temperatures in Phnom Penh are around 79°F (26°C), making it one of the coolest months. Rainfall is also low in December, although not as low as in January and February. Bring an umbrella in case, but you're unlikely to encounter anything more than an afternoon rain shower.
Cambodia is not a huge country, so there's not much latitudinal variation between north and south, but there is variation between the mountains and the lowlands and coast. Temperatures in the highlands of the Cardamom Mountains or the Dangrek Mountains are cooler than on the lower-lying plains, where most of Cambodia's towns and cities are, including Phnom Penh.
Crowds & Costs
December is the peak season for travel, thanks to the cooler conditions that make being outdoors pleasant, the winter holidays in Europe and North America, and the summer holidays in Australia and New Zealand. The temples of Angkor are a top-rated attraction and get crowded. However, it's worth noting that the further you go from central Angkor Wat, the thinner the masses. Book accommodation in nearby Siem Reap well in advance, particularly over Christmas and New Year. The same applies to many other parts of the country, including Battambang, Kampot, Phnom Penh, and the coastal beach resorts.
Prices will also generally be higher in December than in the low season, but Cambodia is a very affordable destination at any time of year. Many locally run hotels and guesthouses will remain at a good value even in the high season. Reserve your first choice early if you're visiting this month.
Where to Go
Where you choose to go in Cambodia will depend on your interests and priorities. Still, most travelers like to combine time in Phnom Penh, Siem Reap/Angkor, and a beach resort near Sihanoukville or an offshore island. Travelers with more time may also include stays in Battambang or Kampot (or both!).
Cambodia's beaches are also appealing this month. Although neighboring Thailand is better known as a beach destination, Cambodia's coast is similar but generally less developed (except for some areas close to Sihanoukville). While December isn't the hottest time of year, the skies will be clear, and many visitors will still find temperatures comfortable for a beach vacation. The white sands and clear seas of islands Koh Rong, Koh Rong Samloem, Koh Ta Kiev, and Koh Russey (Bamboo Island) are particularly idyllic.
Chat with a local specialist who can help organize your trip.
What to Do
December is an excellent time to visit Tonlé Sap for birdwatching. The large inland lake connects to the Tonlé Sap River and eventually the Mekong. While water levels in many of Cambodia's waterways continue to drop this month, the Prek Toal biosphere on Tonlé Sap becomes a haven for birds and birdwatchers. A wide variety of feathered creatures flock here in the drier season. There's a floating village at Prek Toal worth visiting, and the bird sanctuary can easily be visited on a day trip from Siem Reap.
December's dry, cooler weather is ideal for walking or cycling around the enormous Angkor series of complexes without getting overheated or wet. Active travelers may want to extend their cycling trip to the Cambodian countryside.
Events in December
New Year's Eve, Phnom Penh and Siem Reap. Although New Year's Eve on December 31 isn't traditionally celebrated by Cambodians (they have their own Khmer New Year in April), travelers can find a party in Phnom Penh, Siem Reap, or wherever other travelers are hanging out.
Traveling to Cambodia in December? Check out these great itineraries
Rural Adventure in Cambodia: Siem Reap, Battambang & Banteay Chhmar - 14 Days. Be immersed in the wonders of rural Cambodia on this two-week journey through ancient temples, charming villages, and spectacular countryside.
Enchanting Cambodia: Phnom Penh, Battambang & Siem Reap - 8 Days. Begin in Phnom Penh, the capital once known as the "Pearl of Asia." Next, travel to the sleepy heritage city of Battambang before rounding off your trip with a visit to Siem Reap—the gateway to Angkor Wat.