One of the most popular summer and fall activities is fishing, especially fly-fishing. Jack Dennis Sports (50 East Broadway; 307-733-3270), in Jackson, has a large network of guides and also offers dedicated fly-fishing trips.

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It is recommended that first-time hikers hire a guide to explore the National Parks (see Indagare Intelligence: Guides), but many travelers set out unaccompanied. If you go out alone, says Cathy Shill from the Hole Hiking Experience ,“carry bear spray, rain gear, extra clothes, water, food and fire starter, and be sure to tell someone where you are going.”

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You can enjoy a host of activities on and around the mountains during the summer, including horseback riding, paragliding, hot-air ballooning and mountain biking.

For golfers, there are two courses in the valley: the Arnold Palmer–designed Teton Pines (www.tetonpines.com) and the one at the Jackson Hole Golf & Tennis Club (www.jhgtc.com), which was redesigned by Robert Trent Jones. To make arrangements, see the Jackson Hole Web site (www.jacksonhole.com) for a list of recommended outfitters, or ask the concierge at your hotel.

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Jackson Hole is renowned for some of the most difficult terrain in North America—a sign at one of the chairlifts warns: “You must always exercise extreme caution. You could become lost. You could make a mistake and suffer personal injury or death.” At 4,000-plus feet, Jackson Hole’s vertical drop is the longest continuous drop of any U.S. resort. The area draws serious skiers, and the advanced ski classes are packed, mostly with people wishing to improve their off-piste technique. Après Vous Mountain has gentler slopes for beginners, and Rendezvous Mountain offers some lovely intermediate runs, including the wide Amphitheater and Gros Ventre. More seasoned skiers are often found in the 3,000-acre backcountry or in the deep chutes and daredevil trails of the Hobacks or Corbet’s Couloir. The steep and challenging terrain draws more skiers than snowboarders.

Jackson Hole’s Mountain Sports School, which has an office right at the foot of the slopes, is known for its small classes, taught during the high season by some 500 instructors. Reservations are recommended, especially for the children’s classes, though, as one teacher told me, “We always find room for the kids.” If you’re considering a private lesson, try to get Sloane Andrews, a mountain veteran and amazing—read patient, insightful and encouraging—instructor. Sloane, who runs a farmer’s market during the summer, is also a lot of fun and has a wealth of great Jackson Hole stories.

TIP: It’s not official, but for an extra fee, a private teacher can take you up the mountain a half hour before the lifts start so that you can be the first one on the slopes that day.

For the best snowshoeing, sign up with one of the Hole Hiking Experience’s guides. They provide the equipment, know the paths where you’re unlikely to run into anyone else and bring treats, like trail mix and hot chocolate, for sweet breaks along the way.