I'm visiting Switzerland in mid May.?

When coming to Switzerland in all the summer months from May to September. Wear long pants and a short shirt, but it is always important to have a coat or brass or jacket on hand.

The best answer is yes. Dress in layers, so you can adapt to where you are. Sometimes it's quite cool in the mornings and can get quite comfortably warm.

The weather is about the same as in a temperate climate in the US - EXCEPT if you are on a mountain, or high-altitude area, it could be rather cold (near the freezing point).

I'd plan on having layers to shed, or put on! It 'might' get quite warm by day, other than up a mountain, but cool still at night. And we've been travelling through S. Germany/Austria in July when we woke up to SNOW!

Check the weather forecast before you travel!

Have fun. Try some Swiss cheese.

Depends whether you are at the top of the Matterhorn mountain or sitting beside Lake Geneva.