Planning for the weather is an important factor for making your trip to Viet Tri a success, especially when you're splurging. The hottest months are usually June and July with an average temp of 83°F, while the coldest months are January and December with an average of 66°F. The rainiest months in Viet Tri are August, July, June, and September, with each month seeing an average of 14 inches of rainfall.