Planning for the weather is an important factor for making your trip to Bien Hoa a success, especially when you’re splurging. The hottest months are usually March and April with an average temp of 84°F, while the coldest months are January and December with an average of 81°F. The rainiest months in Bien Hoa are September, July, October, and August, with each month seeing an average of 13 inches of rainfall.