The best seasons for the Three Passes trek are autumn, from late September to November, and spring, from March to May. These are the windows when the weather is most stable, the skies are clearest and the high passes are most likely to be passable. Because you will be above 5,000 m on pass days, the choice of month matters more here than on lower treks.
Autumn: late September to November
Autumn is the most popular season. The monsoon clouds have gone, the air is clear and the views of Everest, Lhotse, Makalu and Cho Oyu are at their best. October is the usual peak, with stable weather and the most trekkers on the trail. November is colder, with fewer people and very clear days, but nights in high lodges can fall well below freezing and the passes may hold ice or fresh snow.
Spring: March to May
Spring is warmer and greener lower down, with rhododendrons in bloom in April. Higher up there can be more snow on the passes early in the season and more afternoon cloud later. Cho La and Kongma La can be snowy in March and early April, which changes the difficulty and may require extra gear and caution.
Winter and monsoon
Winter, from December to February, is very cold, and the passes can be closed by heavy snow. Some lodges close. It is not a good time for the Three Passes unless you are experienced and flexible. The monsoon, from June to early September, brings rain, cloud and leeches in the lower forests and poor views, and it is not recommended.
How to choose between autumn and spring
- Choose October if you want the most stable weather and the busiest trail.
- Choose November for quiet trails and sharp views, but bring warmer gear.
- Choose April for flowers and warmer days, but be ready for snow on the passes.
Plan around weather, not only the month
Even in a good season a pass can be unsafe after heavy snow or in strong wind. Your guide will watch the forecast and local reports, and may change the order of the passes or add a waiting day. Build a spare day into the plan, and treat it as part of the itinerary, not a failure.
