Weather is probably a major factor when you plan your trip to Vi Thanh, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually March and April with an average temp of 83°F, while the coldest months are January and December with an average of 80°F. The rainiest months in Vi Thanh are September, October, July, and May, with each month seeing an average of 14 inches of rainfall.