While complex, the physical geography of the region divides conveniently into two principal features: the Rocky Mountains proper and the Great Plains. Extending from Alaska’s Brooks Range and Canada’s Yukon Territory all the way to Mexico, the Rockies sprawl northwest to southeast, from the steep escarpment of Colorado’s Front Range westward to Nevada’s Great Basin. Their towering peaks and ridges form the Continental Divide: to the west, waters flow to the Pacific; to the east, toward the Atlantic and the Gulf of Mexico.
For many travelers, the Rockies are a summer destination, and it starts to feel summery around June. The warm weather generally lasts until about mid-September. The winter, which brings in packs of powder hounds, doesn’t usually hit until late November, though snowstorms can start in the mountains as early as September. Winter usually lasts until March or early April. In the mountains, the weather is constantly changing (snow in summer is not uncommon), so always be prepared. Fall, when the aspens flaunt their fall gold, or spring, when wildflowers bloom, are wonderful times to visit.