Weather will likely play an important role when you plan your trip to Nozawaonsen, 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 74°F, while the coldest months are February and January with an average of 38°F. The rainiest months in Nozawaonsen are December, July, January, and September, with each month seeing an average of 10 inches of rainfall.