There seldom be snow in May. The weather is mild and generally agreeable during may with abundant sunshine and modest rainfall.

Just got back (28 April) and it snowed on the evening of 17 April; not much, but enough to make the surrounding mountains pretty. At an altitude of about 12,000 feet, I would say that it could probably snow just about anytime, but I certainly would not worry about it in May. It gets chilly at night and if the sun is out, its going to be warm enough to take your coat off during the day. We had a wonderful five days there...the only problem we had was the altitude. Be sure and check with your doctor before your visit and see if he/she will give you medication. I was fine, but my wife needed oxygen about two hours a day. Great country (?) and wonderful people.