Planning for the weather is a good way to make your trip to Mishima relaxing and enjoyable, especially when you're splurging. The hottest months are usually August and July, with an average temperature of 23°C, while the coldest months are January and February, with an average of 7°C. The rainiest months in Mishima are June, July, September and October, with each month seeing an average of 313 mm of rainfall.