Taking the local weather in Iwa-kubo into account can help you maximise your time at the pool during your trip. The hottest months are usually August and July, with an average temperature of 19°C, while the coldest months are January and February, with an average of -1°C. The rainiest months in Iwa-kubo are July, October, September and June, with each month seeing an average of 203 mm of rainfall.