Taking into account the local weather in Lyons 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 66°F, while the coldest months are February and January with an average of 28°F. The snowiest months in Lyons are December, January, February, and March, with each month seeing an average of 24 inches of snowfall.