Technically, you can hike the JMT any time you want -- as long as you're prepared for some pretty heavy snowfall. However, the most popular time to hike the JMT is in the summer -- typically, from July to September, although timing can vary based on the previous season's snowfall [source: Pacific Crest Trail Association].
Hikers who choose to trek the JMT in the summer can expect to enjoy balmy temperatures up to about 87 degrees Fahrenheit (31 degrees Celsius). Although some waterfalls run all year, a few dry up by June; wildflowers reach their peak around the same time. At higher elevations, however, subalpine flowers begin to bloom around July.
The downside of a spectacular summer on the JMT? Lots of other hikers. It's hard to mar the trail's beauty, but folks looking for a solitary experience should be aware that the same warm weather and blooming flowers that attracted them for a June hike will likely attract a number of other visitors as well [source: National Park Service]. Also, be sure to bring bug repellant, as warm weather and high water levels are a strong lure for mosquitoes.
Spring and fall on the JMT have their perks as well -- melting snowfall makes spring the best season for lakes and waterfalls, and the relatively few deciduous trees you'll find burst into spectacular color in the autumn. However, since both seasons back up to winter, hikers should be prepared for colder temperatures, path closures and possible snowfall.
The cold and icy conditions that can seep into surrounding seasons are challenging, but what's it like to actually hike during winter? We'll discuss the risks and rewards of winter on the JMT on the next page.