Mount Everest is extraordinarily difficult to climb, even with modern equipment, experienced guides, and bottled oxygen. About two-thirds of climbers who attempt it now reach the summit, a rate that has doubled over the past 30 years. But the death rate has held steady at around 1% since 1990, meaning roughly 1 in 100 climbers with a permit does not come home. The mountain is dangerous not because of any single challenge but because of how many serious hazards stack on top of each other: thin air, extreme cold, unpredictable weather, physical exhaustion, and crowds.
What the Numbers Say About Success and Risk
A University of Washington analysis of all first-time permit holders from 2006 to 2019 (more than 3,600 climbers) found that summit success rates roughly doubled compared to earlier decades. Better forecasting, improved gear, and a larger support infrastructure all contributed. Yet the steady 1% death rate suggests the mountain hasn’t gotten safer in absolute terms. More people summit, but the same proportion die trying. That gap likely reflects the fact that commercial expeditions now attract climbers with less experience, offsetting the gains from better technology.
The Death Zone Above 8,000 Meters
Above roughly 8,000 meters (26,000 feet), the air pressure drops to about a third of what it is at sea level. Your body simply cannot get enough oxygen to sustain normal function. Red blood cells pick up less oxygen with each breath, and without supplemental tanks, most people would lose consciousness within hours. Even with bottled oxygen, climbers operate in a state of severe deprivation. The average wind chill temperature on the summit during the May climbing season is around minus 45°C (minus 49°F), and exposed skin can develop frostbite in as little as seven minutes.
Two altitude-related conditions kill climbers in this zone. Fluid can leak into the lungs, making each breath feel like drowning. Fluid can also accumulate in the brain, causing confusion, loss of coordination, and eventually coma. Both conditions can progress from mild symptoms to life-threatening emergencies within hours, and the only real treatment is descending, which is often impossible when you’re near the summit in deteriorating weather.
Route Hazards on the South Side
The standard route from Nepal begins with the Khumbu Icefall, one of the most objectively dangerous stretches of any climbing route in the world. The icefall is a half-mile-wide cascade of glacial ice pouring over a rock cliff. It fractures into building-sized towers called seracs and splits open into crevasses that can be 30 meters wide. The entire thing is constantly shifting. There is no safe path through it. Climbers cross aluminum ladders lashed together over bottomless gaps and move as fast as possible beneath hanging glaciers that can release massive ice blocks without warning.
Higher on the mountain, the former Hillary Step near the summit has changed dramatically. What was once a near-vertical rock wall is now a 45-to-60-degree slope of snow and ice, littered with unstable rocks. Expedition leaders often call it the “Hillary Slope.” A cornice collapse in May 2024 highlighted how unstable the snow ridge near this section has become. Crossing it takes 20 to 40 minutes in good conditions, but during peak summit pushes, the wait can stretch past 90 minutes.
Crowds and the Oxygen Clock
Everest’s summit window is narrow. Only a handful of days each May offer weather calm enough for an attempt, which means hundreds of climbers often push for the top on the same day. At the final ridge on the south side, everyone clips into a single fixed rope. Two lines form on that rope: one going up, one coming down. Climbers report waiting anywhere from 20 minutes to over 90 minutes in a queue, standing nearly still above 8,000 meters in extreme cold.
This isn’t just uncomfortable. It’s dangerous in a very specific way. Every minute you stand in line, your oxygen tank drains. Climbers carry a limited supply calculated for a moving pace, not for standing still. Running short on the way down is one of the most common scenarios behind summit-day deaths. Starting in 2026, new protocols require dual fixed lines at the Hillary Slope (separate ropes for ascending and descending traffic) to reduce these bottlenecks.
The Weather Window
Summit temperatures in May average around minus 26°C (minus 15°F), with winds averaging 16 meters per second (about 36 mph) and gusting as high as 80 meters per second (nearly 180 mph) in storms. The most extreme air temperature recorded on the summit is around minus 49°C (minus 56°F). Wind speed is the primary factor that determines whether a summit window opens. Climbers and their weather forecasters may wait weeks at base camp for a brief period of reduced winds, sometimes just 24 to 48 hours long.
How Long the Expedition Takes
A standard Everest expedition runs six to eight weeks from arrival in Nepal to return from the summit. Most of that time is spent on acclimatization, not climbing. After reaching base camp at 5,364 meters, climbers make a series of rotations: climbing up to Camp 1, Camp 2, or Camp 3, spending a night or two, then descending back to base camp to recover. Each rotation pushes the body to produce more red blood cells and adapt to lower oxygen levels. Rushing this process dramatically increases the risk of altitude sickness. The actual summit push, from base camp to the top and back, takes only four to five days within that larger timeline.
Years of Preparation Before the Expedition
Everest is not a mountain you train for over a single winter. Most guided expedition companies expect clients to have summited at least two peaks above 6,000 meters and ideally one above 7,500 meters before they’ll accept a booking. A realistic progression from fit beginner to Everest-ready climber takes one to five years, depending on your starting fitness and how quickly you can accumulate high-altitude experience.
The physical requirements go beyond general fitness. You need deep aerobic endurance (the kind built through months of sustained cardio with a heavy pack), leg and core strength for steep terrain in crampons, and the mental resilience to keep making good decisions when you’re sleep-deprived, freezing, and hypoxic. Many climbers who are physically strong enough to summit fail because they can’t manage the psychological toll of weeks of discomfort, boredom, and fear.
What It Costs
The financial barrier is significant. As of September 2025, Nepal’s climbing permit fee for foreigners on the south route in spring is $15,000 per person, up from $11,000 under the previous rules. That’s just the government fee. A fully guided expedition with oxygen, Sherpa support, food, and logistics typically runs $30,000 to $100,000 or more depending on the operator and level of service. Nepal now also requires that every two climbers attempting any peak above 8,000 meters hire at least one guide, adding to the baseline cost. Factor in gear (high-altitude boots, down suits, and supplemental oxygen systems alone can run several thousand dollars), flights, insurance, and the cost of preparatory expeditions on other peaks, and the total investment over several years can easily exceed $100,000.