Taking into account the local weather in Ketchikan is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually July and August with an average temp of 55°F, while the coldest months are February and December with an average of 35°F. The rainiest months in Ketchikan are November, January, October, and September, with each month seeing an average of 16 inches of rainfall.