Weather is probably a major factor when you plan your trip to Tosashimizu, but bear 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 temperature of 25°C, while the coldest months are January and February, with an average of 11°C. The rainiest months in Tosashimizu are June, September, July and August, with each month seeing an average of 345 mm of rainfall.