Planning for the weather is a good way to make your trip to Yudanaka Shibu Onsen relaxing and enjoyable, especially when you’re splurging. The hottest months are usually August and July with an average temp of 69°F, while the coldest months are January and February with an average of 32°F. The rainiest months in Yudanaka Shibu Onsen are July, December, January, and August, with each month seeing an average of 10 inches of rainfall.