The weather can change on a dime. What seems to be a glorious day can very quickly turn into a thunderous downpour of rain. Be prepared for the worst-case scenario. Aspen has four ski mountains to choose from, all accessed through one lift ticket. You could spend the morning skiing the bumps of Aspen and the afternoon cruising on Snowmass Mountain. RFTA, the public transportation system, offers skier shuttles that frequently leave Aspen for the other mountains.