Taking into account the local weather in Mangan is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually June and August with an average temp of 65°F, while the coldest months are January and February with an average of 48°F. The rainiest months in Mangan are July, August, June, and September, with each month seeing an average of 36 inches of rainfall.