Planning for the weather is an important factor for making your trip to Hoi An a success, especially when you’re splurging. The hottest months are usually June and July, with an average temperature of 28°C, while the coldest months are January and February, with an average of 22°C. The rainiest months in Hoi An are November, October, September and December, with each month seeing an average of 475 mm of rainfall.