If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Hadano: The hottest months are usually August and July with an average temp of 76°F, while the coldest months are January and February with an average of 46°F. The rainiest months in Hadano are September, October, June, and July, with each month seeing an average of 8 inches of rainfall.