Planning for the weather is a good way to make your trip to Yakushima relaxing and enjoyable, especially when you’re splurging. The hottest months are usually August and July, with an average temperature of 27°C, while the coldest months are January and February, with an average of 15°C. The rainiest months in Yakushima are June, September, May and July, with each month seeing an average of 364 mm of rainfall.