Planning for the weather is an important factor for making your trip to Kami-renjaku a success, especially when you're splurging. The hottest months are usually August and July, with an average temperature of 25°C, while the coldest months are January and February, with an average of 7°C. The rainiest months in Kami-renjaku are September, October, July and June, with each month seeing an average of 209 mm of rainfall.