Moderate crowds and temperatures in April–May and September–October make these months the best time to visit Utah and its national parks. Spring boasts active wildlife and blooming flowers. Pleasant fall wraps Utah in colorful foliage along the scenic drives. June to August is the season of spectacular activities like Bonneville Speed Week or stargazing, but these months are the hottest and most touristic. December to February can be snowy and freezing up north, and you have a chance to explore ice castles, warm up in the Mystic Hot Springs or ski in dramatic mountains.