May weather can be nice, but cool with sunshine. But Sierra mountain weather being what it is, we've been there on Memorial Day weekend and had about 3" of snow, like just last year. Yes there is snow usually for skiing at the ski locations. We own both Spring and Fall timeshares and try to always lean towards summer as much as we can as we do not ski. Night time temps are always pretty cool in summer and with chances of freezing in early spring and late fall if you are out that late at night or early in the am.