Weather will likely play an important role when you plan your trip to Otsuki, and keep in mind that cheaper options are usually available when the weather isn’t as good. The hottest months are usually August and July with an average temp of 77°F, while the coldest months are January and February with an average of 50°F. The rainiest months in Otsuki are June, July, September, and August, with each month seeing an average of 14 inches of rainfall.