This doesn't sound that great, but it's close enough to where I'll be staying that I still have to go
Guess, in May also could be slushy. Was in Saas Fee in June once, slush surfing in t-shirt. Funny for one day. Don't forget the proper wax
If you still think of Zermatt, I'll be there in two weeks and can ask which lifts will operate in May. Didn't find the information on the homepage. There are night train connections with sleeping facilities from Munich to here, so you wouldn't loose day-time.