In Cambodia, the climate is tropical, hot all year round, with a rainy season from May to mid-November, when the south-west monsoon prevails, and a dry season from mid-November to April. The dry season can be divided into two periods: the first is the least hot of the year, while the second, from mid-February to May, before the monsoon arrives, is the hottest of the year. The monsoon withdraws in early November in the north, and between the middle and the end of the month in the centre-south.
The climate of Cambodia is fairly uniform, because the country is not large. In a typical year, from 1,300 to 1,800 millimetres (51 to 70 inches) of rain fall in inland areas; the rainiest region is the south-west, towards the coast of the Gulf of Thailand, where the rainfall exceeds 2,000 mm (80 in) per year and there are vast areas covered by forest. The climate becomes a bit cooler in the highlands, such as the Cardamon Mountains, which reach their highest point in Phnom Aural, 1,800 metres (5,900 ft) high, whose slopes are covered by an impenetrable forest and are protected by a nature reserve. The mountainous areas, in addition to being the coolest, are also the rainiest: they receive even 5,000 millimetres (197 inches) of rain per year, and may experience some showers in the afternoon even before the monsoon season (February to April).
The coolest month in Cambodia is December, while the hottest months are April and May, when the heat is oppressive; in the rainy season the temperature is a bit lower, but the humidity is higher, so the weather is hot and muggy.
In the capital, Phnom Penh, the daytime temperature is 30 °C (86 °F) in November and December, it begins to rise slightly already in January, and it reaches its highest values in April, with an average of 35 °C (95 °F), but with peaks of 40 °C (104 °F); then it decreases slightly during the long rainy months.
Here are the average temperatures of Phnom Penh.

Throughout the year, 1,400 mm (55 in) of rain fall, with a minimum in January, when it almost never rains, and a maximum in October, with 250 mm (10 in) of rain. The end of the monsoon, therefore, is the wettest period, and has the greatest risk of flooding, especially in the area crossed by the great river, the Mekong.
Here is the average precipitation.

The climate of the ancient capital, Angkor Wat, located in the northwest of the country, is similar to that of Phnom Penh, but lying in the northern part, here the monsoon retreats a bit sooner, in early November; besides, the winter temperature is slightly lower.
Along the coast, the pre-monsoon heating is less pronounced, due to the thermal inertia of the sea, as we can see from the temperatures of Krong Kampot.

Here the rains are more abundant, given that they amount to almost 2,000 mm (80 in) per year; in addition, the rainiest months are July and August, with more than 300 mm (12 in) per month. Here is the average precipitation.

The amount of sunshine in Cambodia is good from December to February, but also in March and April, despite the first thunderstorms, while it's barely sufficient if not low from June to October, because of the cloudiness due to the monsoon. Here are the average daily sunshine hours in Phnom Penh.



For swimming, the sea in Cambodia is warm all year round, as we can see in the following table.

Tropical cyclones

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Cambodia can be hit by typhoons, the tropical cyclones of the western Pacific, which here are quite rare, because they usually pass to the north and hit Northern Vietnam and Laos, moreover, those arriving in Cambodia are generally weakened, because they discharge the bulk of their energy over the coasts of Southern Vietnam, however, they can still bring heavy rains, which can cause flooding. In theory, typhoons can occur between June and December, but generally in Cambodia they pass from mid-October to mid-November, with a maximum at the beginning of November.

When to go

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The best time to visit Cambodia goes from December to mid-February, being the coolest, and also the driest and sunniest of the year. If you want, you can avoid the first half of December, in which sometimes it happened that a typhoon has passed over the country.
For swimming, the best time goes from December to February, even though on the coast the increase in temperature in the period from March to May is less pronounced than in the interior.

What to pack

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All year round, lightweight clothing of natural fibres, comfortable shoes, scarf for the breeze on the coast; from December to March, a sweatshirt for the evening; in the rainy season, light raincoat or umbrella. For the mountains, spring/autumn clothes, raincoat or umbrella, sweater and jacket for the evening, a bit warmer from December to March.
To enter temples, it is customary to remove shoes, dress neatly and cover a little.