Trekking in Nepal in September 2027: Weather, Best Treks and Departures

Last updated 10 October 2026.

Short answer: September is the tail of the monsoon. It is green, quiet and wet, and the mountains hide in cloud for days. I would not send a first-time trekker to the Everest or Annapurna south side before the last week. The exception is Upper Mustang, which sits in the rain shadow and is clear and stable. If September is your only month, take Mustang. Our Monday departures in 2027 are 6, 13, 20 and 27 September.

People ask about September because it is quiet and they hope it is cheaper. Our prices do not change, and the weather is the real cost. The trek I would choose is the Upper Mustang trek, and the rest of this page explains why, with the figures from my own weather guides, the treks to avoid, the festivals, our dates and when to book.

Trekking in Nepal in September 2027 at a glance

What is the weather like in September?

Warm, wet and cloudy on the south side, drier behind the range. These are averages from my own weather guides. Everest rows are station averages (Dingboche is modelled).

Look at the gap between Lumle at 903 mm and Jomsom at 36 mm. The monsoon dumps its rain on the south slopes and has little left for the north side. On the Everest side, Lukla still gets 419 mm, and in the monsoon months visibility problems close its airport about half the time, with around half of flights cancelled. September is the month it starts to clear, and the last week is much better than the first. My Everest weather guide has the full year.

Which treks suit September 2027, and which do not?

These prices hold for 2027. Group size lowers the price per person, and a private trip costs the same as a group.

On Budget you carry your own bag, rooms are shared and trek meals are not included. On Standard there is one porter for every two trekkers, private rooms and all trek meals, and a solo Standard trekker has no porter, so the guide carries up to 10 kg. On Luxury every trekker has a dedicated porter, private deluxe rooms and all meals, and the Everest Base Camp trek uses a helicopter to and from Lukla.

If you do come in September, forest trails are slippery and leeches are active below about 3,000 m. Landslides cut roads without warning, and in 2026 the floods showed how fast. My monsoon trekking guide lists the routes that make sense in the rain, and my Upper Mustang rain-shadow guide explains the one that does.

How crowded is September?

Quiet. About 96,000 international visitors arrived in September 2024 (Nepal Tourism Board, read from a chart, all visitors), well below October. On the Everest trail the crowds start to build in the last week of the month. The villages are green. If you want the trail to yourself and can accept cloud, this is the month. If you want a clear view of Everest, it is not.

Festivals in September 2027

Haritalika Teej, when women fast and celebrate, is on Friday 3 September 2027. Indra Jatra, Kathmandu's eight-day street festival with masked dances and the chariot of the living goddess Kumari, is on Tuesday 14 September. It is a Kathmandu Valley holiday and worth an extra night in the city. Nepali Constitution Day is on Monday 20 September. Dashain begins at the very end of the month with Ghatasthapana, about 30 September, and the main days are in the first ten days of October. Government dates are not yet announced, so treat these as expected. See my Dashain and Tihar 2027 guide.

Our fixed departures in September 2027

These dates are open to join. If none suits you, tell me your dates and I will run the trek privately, even for one person, at the same price.

What about flights, roads and permits?

Our working Manthali window starts around 25 September. Our notes mark the 27 September departure that way, with a midnight pick-up and a four to five hour drive to Ramechhap. The earlier Mondays may fly from Kathmandu, and monsoon cloud makes Lukla unreliable, so keep at least two spare days at the end. The aviation authority sets the dates and I have not seen the official 2027 ones. Luxury flies a helicopter from Kathmandu to Lukla. My Manthali guide has the detail.

Permits are in our price. Upper Mustang is USD 50 a day with a licensed guide and an agency-issued TIMS card. Manaslu is USD 100 a week plus USD 15 a day from September to November. Everest needs the Sagarmatha National Park permit (NPR 3,000), the Khumbu local fee (NPR 3,000) and TIMS (NPR 2,000). Restricted-area permits need 48 hours in government working days. The Beni to Jomsom road that Mustang uses was damaged in September 2026, and I will confirm each road 48 hours before departure. If it is not open I move your dates free.

When should you book a September 2027 trek?

For an ordinary September trek, two to three weeks ahead is enough, because the pressure on flights and beds is low. Add one to two weeks for Mustang or Manaslu paperwork, and book the 27 September Everest departure earlier because it is the first of the autumn rush. My booking guide has the full table.

The deposit is 10 per cent and it is non-refundable, so there is no refund if you cancel. You can reschedule free of charge with at least 72 hours notice (seven days for restricted areas), to any date within one year. If we cannot run your trip, we refund what you have paid, less taxes, bank or card charges and any money already spent on permits or flights. The balance is paid on arrival in Kathmandu, in USD or EUR, cash or by card. Card carries 3.5 per cent and cash carries none. We do not take Nepali rupees from foreign clients. Your licensed guide is named after you book. Kathmandu hotels are not included in any trek price, so I quote them separately.

Questions people ask

Can you trek in Nepal in September? Yes, but pick the route. Upper Mustang is clear and stable. The south side is wet, cloudy and has leeches, and I would not choose it for views.

Is September monsoon in Nepal? Mostly the tail of it. Rain eases through the month and generally ends by mid October. The Pokhara average is still 635 mm.

Is Everest Base Camp open in September? The trail is open, but Lukla gets 419 mm of rain and flights are unreliable. I would only go in the last week, with spare days.

Why is Upper Mustang dry in September? It sits behind the Annapurna and Dhaulagiri ranges. Jomsom gets 36 mm in September against 635 mm at Pokhara.

Are there leeches in September? Yes, in the lower forest on the wet side, below about 3,000 m. Mustang is a high desert, so there are none there.

Will floods or landslides stop my trek? They can. In 2026 they cut roads in several areas. I check each road 48 hours before departure and move your dates free if it is not open.

Is September cheaper than October? No, our prices are the same all year and hold for 2027.

How do you book?

Message me on WhatsApp on +977 9810351300 with your dates, group size and the trek you have in mind. I will tell you which September date I would choose and send the exact quote.

Written by Shreejan Simkhada, CEO of The Everest Holiday, from a family of three generations of family guides. TAAN Member #1586. WhatsApp +977 9810351300.