Mount Everest Can Only Be Climbed for About 10 Days a Year — Here's Why
The world's highest mountain sits in the direct path of the jet stream for 355 days of the year. Every spring, climbers and Everest Base Camp trekkers alike race a window that can open, and slam shut, within hours.
Stand on the summit of Mount Everest on an ordinary day and you would not survive long enough to enjoy the view. For roughly 355 days of the year, the jet stream — a river of high-altitude wind that circles the planet — sits directly on top of the mountain, driving gusts of 150 to 200+ km/h across the summit ridge. Then, for about ten to fourteen days each spring, the jet stream shifts north just enough to let climbers through. That is the entire climbing season, packed into less time than most people spend on a single vacation.
Key facts
- Everest's summit sits in jet-stream winds of 150–200+ km/h for most of the year
- The climbable 'weather window' is typically just 10–14 days, in mid-to-late May
- In spring 2026, roughly 80% of all 1,008 summits happened in a single 10-day span, May 17–26
- Outside spring and a shorter autumn window, standard Everest summits do not happen at all
The mechanism is simple physics with life-or-death stakes. Everest's 8,849-metre summit pokes directly into the polar jet stream, a fast-moving band of upper-atmosphere wind that normally sits over the peak for most of the year, according to meteorologists cited by AccuWeather and Kathmandu-based reporting on the 2026 season. In the pre-monsoon weeks of April and May, as the Indian Ocean monsoon begins building, the jet stream is pushed north off the summit for a short stretch — sometimes just three to seven days, sometimes closer to two weeks. Wind speeds on the summit ridge drop from lethal to merely dangerous, and a queue of expeditions that has been waiting at Base Camp for a month makes its move, together.
That is why Everest's most famous images — the long line of climbers strung along the Hillary Step, dozens of headlamps snaking up the Lhotse Face in the dark — all happen inside the same handful of days. Everyone is chasing the identical narrow gap in the wind, because there usually isn't a second one. This spring, the jet stream parked directly on the summit from roughly May 14 to 18, delaying the first big summit pushes; when it finally lifted, camps mounted a rush that produced most of the season's 1,008 recorded summits in barely ten days, according to mountaineering chronicler Alan Arnette's 2026 season summary.
| Season | Typical window | What happens |
|---|---|---|
| Spring (Mar–May) | ~10–14 days, mid/late May | ~90% of all standard-route summits |
| Autumn (Sept–Nov) | A few days, if any | A handful of summits, far colder |
| Monsoon (Jun–Aug) | None | Snow, avalanche risk, route unclimbable |
| Winter (Dec–Feb) | None | Jet stream sits directly on the summit |
What this means for trekkers
What this means for you
You don't need supplemental oxygen or a summit permit to feel the benefit of this same window. The identical spring weather pattern that finally lets climbers go up is also the clearest, calmest three-to-four-week stretch of the year on the trail to Everest Base Camp itself — mornings with unobstructed views of Everest, Nuptse and Ama Dablam before afternoon cloud rolls up the valley, as it does most days. It's why our guides book mid-April to late May solid every year, and why the same short window that produces record single-day summit counts on the mountain also produces the busiest, and best-looking, weeks on the trail below it.
Outside that window, Everest essentially closes. Autumn offers a smaller, colder echo of the same pattern — a reason some trekkers prefer it for a quieter trail, at the cost of a shorter and less certain break in the wind. Either way, the lesson from 2026 holds: on the world's highest mountain, the difference between a summit photo and a season written off can come down to a handful of days, and everyone on the mountain is watching the same forecast.
Source: AccuWeather; Alan Arnette, Everest 2026 season summary; The Kathmandu Post.
Cover photo: Ezmari Nabizadeh via Pexels (Pexels License).
来源： AccuWeather
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