Planning for the weather is an important factor for making your trip to Thanh Hoa a success, especially when you're splurging. The hottest months are usually June and July, with an average temperature of 29°C, while the coldest months are January and December, with an average of 20°C. The rainiest months in Thanh Hoa are August, September, July and October, with each month seeing an average of 309 mm of rainfall.