Planning for the weather is a good way to make your trip to Wieng relaxing and enjoyable, especially when you're splurging. The hottest months are usually April and March with an average temp of 81°F, while the coldest months are January and December with an average of 72°F. The rainiest months in Wieng are August, July, September, and May, with each month seeing an average of 11 inches of rainfall.