If you're hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Madang: The hottest months are usually October and November with an average temp of 80°F, while the coldest months are July and August with an average of 80°F. The rainiest months in Madang are March, December, April, and February, with each month seeing an average of 23 inches of rainfall.