Planning for the weather is an important factor for making your trip to Mizunami a success, 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 4°C. The rainiest months in Mizunami are July, September, June and August, with each month seeing an average of 291 mm of rainfall.