If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Kepanjen: The hottest months are usually October and September with an average temp of 75°F, while the coldest months are August and September with an average of 74°F. The rainiest months in Kepanjen are January, February, December, and March, with each month seeing an average of 22 inches of rainfall.