Taking into account the local weather in Riggins 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 December and February with an average of 22°F. The snowiest months in Riggins are February, January, October, and December, with each month seeing an average of 5 inches of snowfall.