If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Shizuoka: The hottest months are usually August and July with an average temp of 74°F, while the coldest months are January and February with an average of 44°F. The rainiest months in Shizuoka are July, June, September, and April, with each month seeing an average of 14 inches of rainfall.