Planning for the weather is a good way to make your trip to Zushi relaxing and enjoyable, especially when you’re splurging. The hottest months are usually August and July with an average temp of 76°F, while the coldest months are January and February with an average of 48°F. The rainiest months in Zushi are October, September, June, and July, with each month seeing an average of 9 inches of rainfall.