How Can You Prepare for Changing Weather and Unexpected Delays in the Nepal Himalaya?

Introduction

A clear morning high up in the mountains under the snow-capped peaks can turn into mist, gale force wind or thick afternoon snow in the space of a few hours. If you’re going to do an adventure in the roof of the world then getting your Nepal Himalaya weather preparation right is just as important as putting on your boots. The latest advisories from the Department of Hydrology and Meteorology and the tourism authorities point to the very dynamic nature of the weather in the mountains with the late retreating Monsoon and the arrival of a Western Disturbance being the two main factors that can have a significant impact on mountain travel.

At Explore Himalaya Travel and Adventure we absolutely believe that safety and confidence are the foundation of any great journey. This is a complete guide to everything you need to know about Himalayan weather, the year round climate, the tools you need to do weather forecasting, the issue of Lukla flight delays, the importance of having the right travel insurance for Nepal trekking and of course the definitive ‘what to pack for trekking in Nepal’ list.

Why Himalayan Weather Changes So Fast

Understanding the weather in the Himalayas starts with an appreciation of the very particular geography of South Asia. The sheer scale of the topography gives rise to a very distinct mountain microclimate in which the valleys are bathed in warm subtropical sunshine and the ridges just a few km away are exposed to sub-zero alpine gales.

Temperature fluctuations can be quite erratic. You could be hiking in a T-shirt under the scorching midday sun and then within the space of a few minutes the temperature can drop right through the ice point. That’s why Nepal Himalaya weather preparation is such a case of ‘prepare for the worst’ as the conditions can change very dramatically. The valleys are wind funnels and moisture coming up from the Indian plains will meet the freezing high altitude air and produce quite a bit of rain or snow in a very small area with very little warning.

Nepal Weather Year Round and Choosing a Season

Knowing the Nepal weather year round will of course go a long way to helping you establish the best time for trekking in Nepal.

• Spring (March to May): rhododendrons in full bloom, warm and long days, generally clear skies though you do tend to get cloud building up in the afternoons.
• Summer/Monsoon (June to August): Heavy rainfall, leeches and slippery trails all characteristic. The rain shadow areas (e.g. Upper Mustang) are of course dry.
• Autumn (September to November): the big season after the monsoon is over. October and November are the crisp air, clear skies and superb mountain visibility months.
• Winter (December to February): freezing temperatures and high snow passes, perfect for the lower elevation cultural treks.

For a more in-depth look at seasonal planning have a read of our guide on Climate in Nepal Year Round Travel Guide. To get a more precise idea of the windows available then have a look at Best Time to Trek in Nepal: A Complete Guide.

Monsoon, Western Disturbance, and Heavy Rainfall

The summer Monsoon normally dies down by mid-October, though of course there can be unseasonal showers due to atmospheric anomalies and lingering low pressure systems from the Bay of Bengal. Winter sees the arrival of Western Disturbance weather systems from the Mediterranean which can bring sudden snowfall to the high mountain passes.

Trekkers need to be prepared for slippery paths, swollen river crossings and potential trail blockages due to a Landslide. High quality waterproof clothing and good pack covers are a must. If you do find yourselves in a river valley situation then always follow local warnings (e.g. the Rasuwa Flash Flood Travel Advisory).

Weather Forecasting and Official Alerts

Reliable weather forecasting is your first line of defence. Mountain weather forecasts are inherently subject to a degree of error so the sensible trekker will combine the digital with the local.

• Check the Official Bulletins: keep a close eye on the updates issued by the Department of Hydrology and Meteorology.
• Lodge and Guide Intelligence: the local tea house owners and the experienced guides have a generational knowledge of the micro weather.
• Daily Reality Checks: treat the mountain forecasts as 3-5 day estimates rather than as absolutes.

For safe Nepal safety travel you must never ignore a ranger’s warning of an impending Avalanche or severe storm warning.

Lukla Flight Delays and Buffer Days

Flights to and from Tenzing-Hillary Airport in Lukla are strictly VFR. If the Himalayan weather turns socked in with fog and low cloud then flights are immediately grounded.

• Typical Delays: Lukla flight delays will usually be 24 to 48 hours though of course with prolonged weather systems you can quite easily end up with delays that go well beyond that.
• Manthali Shift: During the peak autumn and spring seasons, flights to Lukla are frequently diverted to Ramechhap (Manthali Airport) to cope with the volume of air traffic. See more on Domestic Flights in Nepal Guide and our Lukla Flight Unforgettable Adventure.
• The Buffer Day Rule: always build in 2 to 3 buffer days (or 1 slack day per 7 to 10 days of trekking) to your itinerary to absorb any unforeseen transport holds without missing your international connections.

Safety on the Trail (Altitude, Avalanche, Landslide)

Mountain safety goes well beyond just being aware of the weather. High altitude trekking presents a whole host of physiological and environmental hazards.

• Altitude Sickness: Altitude sickness (AMS) can affect anyone above 3,000 m. Ascend slowly (300- 500 m per day above 3,000m), stay well hydrated and be aware of the early signs (throbbing headache, dizziness, loss of appetite). See our Acute Mountain Sickness Causes & Symptoms for more on the expert protocols.
• Trail hazards: steep drop-offs, ice patches and unstable scree slopes all require a steady pace and trekking poles.

For a full set of protocols see our resource on Trekking Safety in Nepal Essentials.

Helicopter Evacuation and Travel Insurance

When you absolutely need an emergency intervention due to severe altitude sickness or injury a helicopter evacuation is often the quickest lifesaver. The problem is that helicopters can’t fly through zero visibility fog or in heavy snowstorms.

You absolutely must have comprehensive travel insurance for Nepal trekking. Your policy needs to cover emergency helicopter evacuation up to your max altitude (e.g. 5,500m+), medical repatriation and trip interruption due to weather. See what to look for in our guide on Travel Insurance for Trekking in Nepal. You can also check out our Kathmandu to Lukla Helicopter Flight Services.

What to Pack for Trekking in Nepal

Your gear list has to be adaptable to extreme temperature fluctuations. The right layering will keep you warm, dry and mobile.

• Clothing: Moisture wicking base layers, insulating fleece or down jackets and a breathable, durable shell with reliable waterproof clothing technology.
• Footwear: Broken in waterproof hiking boots, warm merino wool socks and camp sandals.
• Essential gear: Decent trekking poles, a high-lumen headlamp with spare batteries, dry compression sacks, a high capacity power bank (batteries drain very quickly in the cold) and microspikes for icy trails.

For a very granular breakdown see our guide Gears and equipment for trekking in Nepal.

Route Notes: Weather Realities Across Popular Treks

• Everest Base Camp: High altitude cold and the volatility of the flight to Lukla are the two main issues. Acclimatization is absolutely key. Check out our own package at Everest Base Camp Trek Package.
• Annapurna Circuit: You have to cross Thorong La Pass in the morning within the weather window before the high winds and snow flurries come in. Our route details are over at Annapurna Circuit Trekking Guide.
• Manaslu Circuit: A remote restricted area trek through deep river valleys and high mountain passes. See our itinerary here Manaslu Circuit Trek Package.

Conclusion

Getting your head around the changing weather, getting the right permits and managing the logistics of operating in a foreign mountain range can be a real headache. Explore Himalaya Travel and Adventure removes all that stress. We have decades of experience on the ground, professional mountain guides who are fully licensed, 24/7 support from our Kathmandu office and itineraries that are specifically tailored to your own pace. You’re in safe hands from the moment you arrive until the moment you leave.

Our standard transparent tour packages will normally include airport transfers, domestic flights, an experienced government licensed guide and porter, standard teahouse accommodation, three meals a day during the trek and all requisite conservation and park permits. International flights, personal travel insurance, tips and personal gear are normally not included.

Ready to go on your dream Himalayan trek with absolutely zero stress? Get in touch with Explore Himalaya Travel and Adventure and we’ll put together your tailor made trek itinerary.