Cho Oyu means “Turquoise Goddess” in Tibetan and sits just 20km west of Everest, sharing its base camp plateau and benefiting from the same post-monsoon weather window. Its standard Northwest Face route is classified as the least technically demanding of the 8,000m peaks — but that description requires context. “Least demanding” at 8,000m still means extreme altitude, serious cold, and physiological demands that are non-linear above 7,500m. The 42% overall success rate — highest of any 8,000m peak — belongs to a population of climbers who are typically more experienced and better prepared than average 8,000m permit holders.

How to read these numbers: Success is defined as reaching the true summit (8,188m). Data covers all permitted expeditions 1990–2025 from the Tibet side (primary route) and the Nepal side (rare). Pre-monsoon and post-monsoon seasons are both included, though post-monsoon accounts for over 90% of all attempts.

Cho Oyu’s primary season is post-monsoon, with the October window producing the highest historical success rates. The post-monsoon weather pattern on the Tibetan plateau is more predictable than the pre-monsoon Himalayan jet stream window that Everest climbers work with — a key reason Cho Oyu is preferred as a first 8,000m objective.

October 1–20 consistently produces the highest Cho Oyu summit rates, aligning with post-monsoon stabilization and before the winter jet stream descends over Tibet. Teams that complete two full acclimatization rotations before their October summit push outperform those who attempt with a single rotation by approximately 18 percentage points — the largest acclimatization effect of any peak in this database.

The Northwest Face is Cho Oyu’s standard route and accounts for nearly all attempts. The Southwest Pillar is a rarely-attempted technical alternative that attracts elite alpinists seeking a more demanding line on a less demanding peak. The success rate difference reflects both objective difficulty and climber self-selection.

The Northwest Face route’s non-technical character should be understood in relative terms. Above Camp 3 (7,700m) the terrain steepens and the altitude effects become severe regardless of technical grade. Climbers who treat the approach as a “walk” often find the final 500m to the summit the most demanding terrain they have ever encountered.

The 27-point gap between guided and independent Cho Oyu success rates is larger than on Everest and reflects a specific pattern: independent teams on Cho Oyu frequently compress acclimatization rotations and misjudge the October weather window. Guided teams enforce the two-rotation protocol and have established relationships with weather forecasting services that provide actionable guidance.

Cho Oyu’s experience-level data tells a clear story: the jump from 7,000m to 8,000m altitude is physiologically significant regardless of route difficulty. Climbers who arrive with prior 8,000m experience perform at nearly twice the rate of first-time 8,000m climbers, even on the non-technical Northwest Face.

From The Himalayan Database expedition records and post-expedition operator reports, 2000–2025, Northwest Face.

Cho Oyu has a moderate rescue profile relative to its altitude. Helicopter access is available to approximately 6,000m on the Tibet plateau approach, but high-camp rescues above that altitude require human evacuation over significant terrain. The relatively lower rescue rate compared to Everest reflects both the smaller permit pool and the stronger average experience level of Cho Oyu permit holders.

China’s periodic permit restrictions on the Tibet side add a unique logistical risk to Cho Oyu: in seasons where permit access is restricted or revoked mid-expedition, teams face significant financial losses in addition to the standard mountain risks. Expedition insurance that covers permit cancellation and early-season evacuation is advisable for all Cho Oyu teams.

Cho Oyu’s success rate has remained the most stable of any 8,000m peak over the past 35 years. The post-monsoon weather pattern on the Tibetan plateau is more consistent than the Himalayan monsoon, and the improving commercial logistics from the Tibet side have kept outcomes steady even as permit numbers have grown modestly. The primary variable affecting year-to-year rates is China’s permit policy — seasons with restricted access see fewer attempts and slightly higher rates from the more experienced self-selected teams that still obtain permits.

Unlike Everest and Mont Blanc, where declining success rates reflect structural environmental changes, Cho Oyu’s plateau since 2008 is a positive stability story. The improving Tibet-side commercial infrastructure and the consistently experienced permit holder pool have kept the success rate at the highest level of any 8,000m peak in the database. The primary future risk is regulatory — China’s permit policy on the Tibet side remains unpredictable.