Taking into account the local weather in Phumĭ Cheung Koŭ can help you maximize your time at the pool during your trip. The hottest months are usually May and April with an average temp of 83°F, while the coldest months are January and December with an average of 81°F. The rainiest months in Phumĭ Cheung Koŭ are September, July, August, and June, with each month seeing an average of 25 inches of rainfall.