If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Kampong Cham: The hottest months are usually March and April with an average temp of 85°F, while the coldest months are January and December with an average of 80°F. The rainiest months in Kampong Cham are September, October, August, and July, with each month seeing an average of 11 inches of rainfall.