Planning for the weather is a good way to make your trip to Naoshima relaxing and enjoyable, especially when you’re splurging. The hottest months are usually August and July, with an average temperature of 25°C, while the coldest months are January and February, with an average of 8°C. The rainiest months in Naoshima are July, June, September and August, with each month seeing an average of 182 mm of rainfall.