Cambodia's climate is governed by the monsoon winds, which define two major seasons. From mid-May to early October, the strong prevailing winds of the southwest monsoon bring heavy rains and high humidity. From early November to mid-March, the lighter and drier winds of the northeast monsoon bring variable cloudiness, infrequent precipitation, and lower humidity. The weather between these seasons is transitional.
Maximum temperatures are high throughout the year, ranging from about 82 to 83 °F (28 °C) in January, the coolest month, to about 95 °F (35 °C) in April.
The rains come when the winds shift into the southwest monsoon from May to November. During this period, you can expect the most precipitation in Cambodia throughout the months of September and October.
Cambodia heats up steadily from February to April, with temperatures peaking as high as 40°C in April. Temperatures remain high in May and June, and the southwest monsoon brings in more humidity and some very sticky days! From July through October there will certainly be some rainfall, but it usually comes in short showers.
Unless you're in remote areas with bad roads, travelling is perfectly comfortable during these months. It's also nice to see the rice paddies and tropical foliage at their most green and lush.
The best months to visit Cambodia are December and January, with dry weather and lower humidity levels – of course, this is also the busiest time of year when you can expect some crowds and higher prices.
 "Within the Royal Palace compound is the extravagant Silver Pagoda, also known as Wat Preah Keo or Temple of the Emerald Buddha. It is so named for its floor, which is covered with five tons of gleaming silver. You can sneak a peek at some of the 5000 tiles near the entrance, but most are covered to protect them.")
