Planning for the weather is a good way to make your trip to Shinano relaxing and enjoyable, especially when you’re splurging. The hottest months are usually August and July, with an average temperature of 21°C, while the coldest months are January and February, with an average of 0°C. The rainiest months in Shinano are July, December, January and August, with each month seeing an average of 255 mm of rainfall.