Weather is probably a major factor when you plan your trip to Tosashimizu, 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 78°F, while the coldest months are January and February with an average of 52°F. The rainiest months in Tosashimizu are June, September, July, and August, with each month seeing an average of 14 inches of rainfall.