Come for one season. Pack for them all.
Umbrellas. Sweaters. Hiking Shoes. Don't end up like one of those tourists in shorts standing on the top of a snowy mountain in July wondering why they're cold. The weather is unpredictable in Switzerland, even in the summers. It's like the month of March just keeps repeating itself all year round. Best bet in the summers is to invest in a pair of pants that can double as pants and shorts. Zipping off half your pants mid-hike is a popular activity in Switzerland, and you won’t want to miss out.