Yellowstone’s famed Old Faithful  has predictable eruptions that delight crowds every 90 minutes or so, while Mammoth Hot Springs  features an ever-changing palette of pastel-colored springs. Bucolic Lamar Valley in the northeast corner  is the best place to see wolves and other wildlife.
Grand Canyon of the Yellowstone  may be the park’s most spectacular feature, with the river plummeting 308 feet over Lower Falls. South of here is Yellowstone Lake , the largest high-elevation lake in North America.
Capped by 13,772-foot Grand Teton, the Teton Range rises abruptly from the valley floor, with the Snake River winding sinuously beneath ragged peaks. Craig Thomas Discovery and Visitor Center  provides a great introduction to the park.
Wyoming’s preeminent tourist town, trendy Jackson  occupies the southern end of the valley called Jackson Hole. Four arches created from hundreds of elk antlers frame Town Square , host to faux shoot-outs and farmers’ markets all summer.
Jackson is crowded with dozens of galleries, and the National Museum of Wildlife Art  is just north of town. Winter sleigh rides  draw visitors to the National Elk Refuge , while skiers challenge the slopes of Jackson Hole Mountain Resort . All sorts of summer fun fill the calendar, from river rafting  to The Grand Teton Music Festival .
Yellowstone summers start late (June) and are relatively short. The vast majority of visitors to Yellowstone and Grand Teton arrive in the hectic months of July and August, when the snows are gone, temperatures are warm, skies are often clear, local businesses and attractions are all open, and wildlife are readily visible. Anyone arriving at other times may find closed facilities and campgrounds, along with minimal Park Service staffing.
Fall is a favorite time to visit the parks. The crowds have diminished, most businesses and campgrounds are still open, and on crisp mornings the air is filled with the bugling of elk. Temperatures drop as fall progresses and the snow gradually moves down the mountains; most Yellowstone National Park roads are closed by early November.
Yellowstone winters are cold, snowy, and starkly beautiful. Park access is by snowcoach or guided snowmobile. Jackson Hole  is a major winter destination, with three ski resorts and a wide range of winter activities. West Yellowstone is popular with snowmobilers and cross-country skiers, while Gardiner serves as a base for wolf-watchers.
Entrance to Yellowstone costs $25 per vehicle ($12 by bicycle, foot, skis, or bus). The pass includes entrance to both Yellowstone and Grand Teton National Parks for seven days. For longer stays, an annual pass ($50) covers both parks and the Interagency Annual Pass ($80 per year) is good for all national parks.
Most roads in Yellowstone close on the Monday after the first Sunday in November and usually open again by mid-May. Only the road between Mammoth and Cooke City is kept plowed all winter. Plowing begins in early March, with the roads connecting Mammoth to West Yellowstone opening first (typically mid-April). Most campgrounds and visitor centers are open May-September.
The vast majority of visitors arrive by car, though there are daily flights into Jackson from many major cities. You can also fly into a regional airport such as Salt Lake City, Utah or Billings, Montana and rent a car. Buses and vans provide connections between Jackson Hole and Salt Lake City. Most national chains offer car rentals in Jackson, with fewer options in the towns of Cody and West Yellowstone. Public transportation within the parks is nonexistent.
Lodging reservations are highly recommended for midsummer travel throughout the region, especially over holiday weekends. Reserve well ahead of your trip for the best options. Winters can also be busy, particularly in Jackson over the Christmas-New Year’s holiday period. Some of the most in-demand lodges fill months ahead of time.