Weather can make or break a roadtrip, so here's some data about year-round temperatures in Leuen to help you plan yours: The hottest months are usually September and August with an average temp of 83°F, while the coldest months are February and March with an average of 82°F. The rainiest months in Leuen are November, October, September, and July, with each month seeing an average of 15 inches of rainfall.