Taking into account the local weather in Wengen 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 54°F, while the coldest months are January and February with an average of 25°F. The rainiest months in Wengen are July, June, August, and May, with each month seeing an average of 9 inches of rainfall.