If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Rebun: The hottest months are usually August and September with an average temp of 62°F, while the coldest months are January and February with an average of 29°F. The snowiest months in Rebun are March, January, February, and December, with each month seeing an average of 98 inches of snowfall.