Taking into account the local weather in Koh Rong Sanloem is an important factor for planning your visit, especially if you plan to spend your trip poolside. 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 Koh Rong Sanloem are September, July, August, and June, with each month seeing an average of 25 inches of rainfall.