If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Jinju: The hottest months are usually August and July with an average temp of 73°F, while the coldest months are January and December with an average of 38°F. The rainiest months in Jinju are July, August, September, and June, with each month seeing an average of 9 inches of rainfall.