The Khumbu has two good seasons, one viable cold season, and one to avoid. Which of the two good ones you choose depends on whether you value clear air or warm air, and whether you want to see Base Camp as a working expedition city or as bare glacier.
The figures below are for the upper valley, where your decision actually gets made.
The Seasons Compared
| Season | Months | Visibility | Night at Gorak Shep | Crowds |
|---|---|---|---|---|
| Autumn | Late Sep – Nov | Best of the year | -10 to -18 °C | Highest, peaking in late October |
| Spring | Mar – mid May | Good, hazier after mid April | -8 to -15 °C | High, with expedition traffic |
| Winter | Dec – Feb | Excellent, very clear | -18 to -25 °C | Very low |
| Monsoon | Jun – mid Sep | Poor, cloud and rain | -5 to -12 °C | Very low |
Autumn: The Default Answer
From the last week of September to the end of November, the monsoon has scrubbed the air clean and winter systems have not arrived. Mornings are reliably cloudless, afternoons stay clear, and Lukla flights operate close to schedule — which matters more on this trek than on any other in Nepal.
October is the single most popular trekking month in the country, and you will feel it: full lodges at Dingboche and Gorak Shep, queues on the Namche climb, and a need to book early. November trades a little warmth for the clearest air of the entire year and noticeably thinner crowds by mid-month.
Base Camp in autumn is largely empty — a few Lhotse and Ama Dablam expeditions at most, and otherwise bare ice and moraine at the foot of the Icefall. Some trekkers find that more moving than the spring tent city.
Spring: Warmer, and the Climbing Season
March to mid-May is the other strong window. It is warmer at every altitude, the days are longer, rhododendron flowers in the lower valley through April, and Lukla flights are generally reliable.
The distinctive feature is Base Camp itself. Every Everest and Lhotse expedition stages here in April and May, so the moraine becomes a city of several hundred tents with helicopters coming and going and the Icefall doctors' route fixed above. If seeing an Everest expedition at work is part of why you are going, spring is the only season for it.
The cost is clarity. From mid-April, haze and afternoon cloud build, and the Kala Patthar panorama is softer than in November. Late March to mid-April is the sweet spot: bloom below, tents above, air still sharp.
Winter and Monsoon
Winter (December to February)
Superb visibility, empty trails, and soft lodge prices — against nights of -25 °C at Gorak Shep, short daylight, some high lodges closed for the season, and a real chance of snow closing the trail above Lobuche for a day or two. We run it for experienced trekkers with a -20 °C bag and flexible dates, and we recommend against it for a first Nepal trek. The Everest View Trek is the better winter option in this region.
Monsoon (June to mid September)
Not worth it here. The Khumbu sits south of the main divide, so it gets the full monsoon: cloud for days, leeches in the lower forest, and Lukla flights cancelled routinely. If your dates are fixed in July or August, go north of the Himalaya instead — see our monsoon trekking guide.
Month by Month
| Month | Verdict |
|---|---|
| January | Coldest. Clear and empty. Experienced trekkers only. |
| February | Cold but improving, excellent visibility, very quiet trails. |
| March | Season begins. Cool at altitude, clear, expeditions arriving. Good choice. |
| April | Best of spring. Warm, bloom below, Base Camp fully active. Busy. |
| May | Warm and hazy, afternoon cloud, summit attempts underway. Fine early, fading late. |
| June | Monsoon arrives. Avoid. |
| July | Wettest. Avoid. |
| August | Wet. Avoid. |
| September | Unreliable until about the 25th, then the first clear windows. A quiet, good bet late. |
| October | The most reliable month of the year, and the busiest. |
| November | Clearest air of all, cooling fast, quieter after mid-month. Our own favourite. |
| December | Cold, clear, quiet. Workable for well-equipped trekkers early in the month. |
If we had to pick one fortnight: the first half of November. If you want Base Camp alive with expeditions: the first half of April.
Festivals Worth Timing Your Trek Around
The Khumbu has its own religious calendar, and two of its festivals are worth building an itinerary around if your dates are flexible.
- Mani Rimdu at Tengboche — a three-day festival of masked dances, prayers, and blessings at the Khumbu's principal monastery, held over the full moon of the ninth Tibetan month, usually late October or November. It is the single best cultural experience available on this trek, and lodges at Tengboche are booked out for it.
- Dumje — a Sherpa village festival in June or July, mostly at Namche, Khumjung, and Thame. It falls in the monsoon, so few trekkers see it.
- Losar — Tibetan New Year in February, marked quietly in Khumbu villages with family gatherings and monastery prayers. Quiet trails and a genuine welcome.
If Mani Rimdu matters to you, tell us when you enquire rather than after booking — the dates shift with the lunar calendar each year, and Tengboche accommodation needs securing months ahead. Our Tengboche and Sherpa culture guide explains what happens at the festival and how to attend respectfully.
