Cambodia Weather. Tropical monsoon climate. Monsoon season is from May to November. The most pleasant season is the dry season, from November/December to April. In the north, winters can be colder, while throughout most of the country temperatures remain fairly constant. There is often seasonal flooding in Phnom Penh and the rest of Cambodia in late-July and early-August; travel may be disrupted.
Lightweight clothing and cottons are worn all year. Rainwear is essential during the rainy season.