Weather will likely play an important role when you plan your trip to Sasebo, 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 76°F, while the coldest months are January and February with an average of 48°F. The rainiest months in Sasebo are July, June, August, and September, with each month seeing an average of 11 inches of rainfall.