Nepal's outdoors is open all year; the question is what you want from it. The Himalaya has two peak seasons, a wet summer and a cold winter, and each one changes which trails make sense. Here's the honest version.
Autumn: October–November
The classic season. The monsoon has washed the dust out of the air, skies are at their clearest, temperatures are comfortable in the hills and cold but manageable high up. Everything is open — Everest, Annapurna, Langtang, Manaslu, all of it. The cost is company: the popular trails and Lukla flights are at their busiest, and tea houses in Namche or Manang fill up. Book ahead, or pick a quieter region.
Best for: any classic trek, the big views, first-time trekkers. Also the ideal months for day hikes and runs around Kathmandu, and the Dashain and Tihar festivals fall in this window.
Winter: December–February
Cold, dry and often stunningly clear, especially in December. Lower treks — Poon Hill, Mardi Himal, Langtang Valley, Helambu, the Kathmandu Valley rim — are excellent and quiet. High passes are another matter: Thorong La, the Everest Three Passes and Larkya La on the Manaslu Circuit can be closed or dangerous after snowfall, and tea houses at the highest villages may shut. Everest Base Camp is still possible for the well-prepared; expect nights far below freezing.
Best for: lower and mid-altitude treks, crisp valley hikes, road cycling in the Kathmandu and Pokhara valleys.
Spring: March–May
The second big season. Rhododendron forests turn red and pink in March and April, days get longer and warmer, and the high passes reopen. Haze builds in the lowlands as the season goes on, so mountain views from the hills around Kathmandu fade by late April, though high up they remain sharp. May is warm, occasionally stormy and the traditional month of Everest summit attempts.
Best for: Annapurna and Everest treks, rhododendron walks such as Poon Hill and Phulchowki, spring running before the heat.
Monsoon: June–September
Rain arrives from the south-east in June and dominates until mid-September. Trails in the middle hills are muddy and leech-rich, flights are delayed, clouds hide the mountains and landslides can close roads. But there are exceptions that make the monsoon a genuine option: the rain-shadow regions north of the main Himalayan chain — Upper Mustang, Upper Dolpo, Nar Phu and to some extent Manang — stay largely dry and are at their best now. Forests are lush and lower trails are empty.
Best for: Upper Mustang and Dolpo, early-morning runs before the afternoon rain, patient hikers who don't mind cloud.
Quick picks by activity
- High treks with passes: October–November, then April–early May
- Everest Base Camp: October–November, March–April; December for the hardy
- Lower treks (Poon Hill, Mardi Himal, Langtang, Helambu): October–April
- Kathmandu Valley day hikes: October–March for views, any month for the walk
- Running: October–February for cool, clear mornings
- Cycling and mountain biking: October–April on dry trails and roads
Whenever you go, plan for the season you'll actually get: download your maps before the clouds roll in, pack for the temperature at your highest sleeping point, and leave slack in the itinerary for weather. Trailma's elevation profile tells you how high you'll be each night — which tells you how warm to pack.
