Planning for the weather is a good way to make your trip to Togo Onsen relaxing and enjoyable, especially when you’re splurging. The hottest months are usually August and July with an average temp of 75°F, while the coldest months are January and February with an average of 42°F. The rainiest months in Togo Onsen are July, September, August, and June, with each month seeing an average of 11 inches of rainfall.