Half Dome is the hardest day hike in Yosemite National Park. The full round trip runs over 17 miles. Total elevation gain from the Valley floor is roughly 4,800 feet. Most hikers finish in 10 to 14 hours. The hike starts at Happy Isles, elevation 4,035 feet. It ends at the summit, 8,844 feet above sea level. Here's what actually taking on this trail involves.
A permit is required for the final cables section, and it's genuinely hard to get. The National Park Service issues a maximum of 300 permits per day during cables season, split into 225 for day hikers and 75 for backpackers. Most hikers apply through the preseason lottery, which runs March 1 through 31. Results arrive by email in mid-April. A smaller daily lottery also runs two days before each hike date, opening at midnight Pacific time and closing at 4 p.m. that same day.
The application fee is $10 per application. That fee is charged whether or not a permit is awarded. The permit fee itself is $10 per person, charged only if a permit comes through. That fee is refundable under two conditions. Either the hike is cancelled by 11:59 p.m. Pacific time the day before, or the cables aren't operational for some reason. Applications go through Recreation.gov or by phone.
The cables themselves only go up for part of the year. The season runs from the Friday before the last Monday in May through the day after the second Monday in October. Outside that window, the cables come down. The final pitch becomes a serious rock climb rather than a cable-assisted scramble. Check current cable status directly with the park before planning around a specific date. Exact dates shift slightly year to year based on weather and crew availability.
The route starts on the Mist Trail, the same trail used for Vernal Fall and Nevada Fall. The first 5.5 miles climb about 1,000 feet to the top of Vernal Fall. From there, the trail gains another 1,000 feet over 2.5 miles to reach the top of Nevada Fall. This stretch alone is a genuinely popular standalone hike. Many visitors do it without attempting the full Half Dome route at all.
Beyond Nevada Fall, the crowd thins out fast. The trail continues through forest and past Little Yosemite Valley, a popular backpacker campsite. Then it begins the long climb toward the subdome. The subdome itself is a steep, exposed set of granite switchbacks. It's the last real gut check before the cables. It catches a lot of hikers off guard, coming after already covering 7 or 8 miles.
The cables section is the final 400 feet of elevation gain. It climbs a granite slope that runs close to 45 degrees in places. Two steel cables run parallel up the rock, spaced about a shoulder-width apart. Wooden boards are laid across as footholds every few feet. Hikers move hand over hand up the cables, often waiting in a line behind slower climbers. Gloves help a lot here. Many hikers bring a cheap pair just for this stretch. They leave the gloves behind at the base for the next person.
Weather matters enormously on this section. Wet granite is dangerously slick. The cables are the single most common site of serious injury and fatality on this hike. Afternoon thunderstorms are common in the Sierra Nevada during summer. Lightning on an exposed granite dome is a real, documented risk. Starting early matters here. Getting off the cables well before early afternoon isn't just a suggestion. It's the single most important safety practice on this entire route.
The summit itself is a broad, mostly flat granite expanse. It's large enough that it never feels as crowded as the cables did getting up. The view stretches across Yosemite Valley, Tenaya Canyon, and the high country toward Tuolumne Meadows. Most hikers spend 30 minutes to an hour at the top. Then comes the long descent, which takes nearly as much time and energy as the climb itself.
Training matters more for this hike than almost any other trip-planning detail. Ten to 14 hours on rough, exposed terrain at elevation is a serious physical undertaking, even for regular hikers. Multiple long training hikes in the weeks before the trip make a real difference. Ideally those training hikes include real elevation gain, not just flat mileage. Attempting this as a first serious hike of the season is a common and avoidable mistake.
Water and food planning deserve real attention too. There's no reliable water source past Nevada Fall for most of the season. The exposed granite sections offer no shade at all. Most experienced hikers carry at least 3 to 4 liters of water. A real water filter as backup is worth the extra weight. Bring enough calories to genuinely fuel a 10-plus hour effort. A couple of energy bars alone won't cut it.
Starting time matters as much as physical preparation. Most successful hikers begin well before sunrise, often between 4 and 6 a.m. That timing avoids the worst midday heat on the exposed sections. It also clears the cables before afternoon storm risk builds. It leaves enough daylight margin too, for a hike that can easily run longer than planned.
For hikers who don't get a permit, the trail up to Nevada Fall remains a genuinely worthwhile hike on its own. It doesn't need the cables at all. The Mist Trail section up to Vernal Fall is shorter still. It's one of the most popular hikes in the entire park. Neither substitute delivers the summit view. Both are real, complete hikes in their own right, not consolation prizes.
Half Dome isn't a hike to attempt on a whim. The permit system exists precisely because demand vastly outpaces what the trail and cables can safely handle. Hikers willing to plan months ahead have a real shot at this hike. Serious training and an early start make the difference too. Together, those three things are what make Half Dome one of the defining hikes in the entire National Park System.
Permit strategy is worth planning early, not as an afterthought. The preseason lottery in March offers the best odds for anyone with real flexibility on dates. Applying for multiple date options, and listing genuine alternate dates, both meaningfully improve the actual odds of getting picked. The daily lottery two days out works well as a backup, especially for smaller groups willing to take a specific, less-popular weekday.
Gear beyond gloves matters too. Sturdy hiking shoes with real traction help enormously on the granite sections, wet or dry. A headlamp is essential given how early most hikers start in the dark. Trekking poles help on the steep Mist Trail sections, though many hikers stow them before the cables since both hands are needed there. Sunscreen and a hat matter on the exposed subdome and summit, where there's no shade at all.
Timing within the cables season also matters, not just the season itself. Late May and early June often bring cooler temperatures and lingering snowmelt on the approach trails, which can make footing trickier in spots. September and early October tend to bring more stable weather and smaller afternoon storm risk, though days are shorter by then. Midsummer offers the most reliable cable access but also the biggest crowds and the highest afternoon thunderstorm risk of the whole season.