Annapurna Base Camp Weather by Month — Temperatures at 4,130 m

Most weather pages for this trek quote a single temperature for the whole route, which is useless — you pass through about 2,600 m of vertical in four days. The lodge at Bamboo and the lodge at Base Camp are different climates on the same afternoon.

This is what to expect by month, banded by altitude. For choosing a season across Nepal as a whole, we have written that separately; this page is the Sanctuary specifically.

The one thing that is true in every month

It freezes at Base Camp at night, all year. At 4,130 m, in an enclosed basin that loses heat to a clear sky, there is no month in which you should plan for a warm night. People arrive in May with a summer sleeping bag and spend the night awake.

A bag rated to around -10 °C is the right call in any season. Lodge blankets exist; do not build your plan on them.

By month

Month	Base Camp night	Lower trail day	Verdict
Oct–Nov	−5 to −10 °C	12–18 °C	Clearest and most settled
Dec–Jan	−10 to −20 °C	6–12 °C	Sharp, empty, cold; snow in the Sanctuary
Feb–early Mar	−10 to −15 °C	8–14 °C	Avalanche window — see below
Late Mar–May	−2 to −8 °C	15–22 °C	Warm, green, hazier by the week
Jun–Sep	0 to −5 °C	18–25 °C, wet	Monsoon. We do not run it

Treat these as the usual range rather than a guarantee. A clear night in late October at Base Camp can sit at the bottom of that band, and a settled day in May can beat the top of it.

October and November: the honest best

The monsoon has washed the air and left, and the winter weather has not arrived. Visibility is at its best in the year, the trail is dry, and the Sanctuary holds its colour. Nights are cold but not punishing.

The cost is company. This is the busiest window on the route, Chhomrong lodges fill, and at Base Camp in late October you will not have the dawn to yourself. We think it is worth it.

December and January: better than their reputation

Cold, bright, and extremely quiet. The air in December is often the clearest of the entire year, the lower forest is pleasant to walk in, and you may have whole afternoons without seeing another party.

What you accept in exchange: snow in the upper Sanctuary, some lodges above Deurali closed or minimally staffed, and nights at Base Camp that are genuinely severe. It is a good month for an experienced walker with proper kit and a bad one for a first Himalayan trek.

February and early March: the window we decline

This is the part of the year most operator pages skip, and it is the one with real consequences.

The trail between Hinku Cave, Deurali and Machhapuchhre Base Camp runs beneath steep open slopes that load with snow. After winter accumulation, with the spring sun beginning to work on the snowpack, that section becomes the most hazardous ground on the trek. It has killed trekkers — four Australians in March 2001, and four South Korean trekkers with three Nepali guides in January 2020.

We do not sell departures in February or early March following a heavy winter. If you ask us for those dates we will tell you why and offer you Poon Hill or Mardi Himal instead, neither of which carries comparable exposure.

In any season, that stretch is crossed early in the morning before the sun softens the slopes above it, and after fresh snow it is not crossed at all.

Late March to May: warm, green, and increasingly hazy

Rhododendron comes into flower through the forest below Chhomrong from late March, and by April the lower valley is genuinely beautiful in a way October is not. Days are warm, nights at altitude are the mildest of the year.

The trade is clarity. Haze builds through spring as the pre-monsoon heat does, and by mid-May afternoon cloud is routine. Mornings stay sharp — if you are walking in May, the view you came for is before ten o'clock.

The monsoon, and why we say no

June to September brings heavy rain, leeches in the forest below Chhomrong, landslide risk on the access road, and cloud that removes the point of going. The Sanctuary is at its least rewarding and the drive is at its most dangerous.

Some operators run it. We do not, and if that is the only window you have, we would rather send you to Upper Mustang, which sits in the rain shadow and is at its best precisely when the rest of the country is underwater.

The advantage nobody mentions: it works in cloud

This is a real reason to pick this trek if your dates are fixed and the forecast turns.

Ridge treks — Poon Hill, Mardi Himal, Khopra — are entirely about the panorama. A grey day removes the reason you came. The Sanctuary is an enclosed gorge, and walking up it between vertical walls with cloud moving through is atmospheric rather than disappointing. The Base Camp bowl also has a habit of clearing at dawn after an overcast afternoon.

It is the most weather-robust trek in the region, and that is worth something October cannot sell you.

Forecasts, and how much to trust them

Mountain forecasts for a specific basin at 4,130 m are indicative at best. What matters more is the decision made on the morning by someone standing in it — which is why the call on the avalanche section belongs to the guide on the day rather than to an office working from a schedule.

For live conditions, the package page for our seven-day Annapurna Base Camp trek carries a current reading for the Base Camp location itself.

Weather determines what you see; the cumulative ascent determines how you feel, and the lodges above Chhomrong determine how warm you are at night. The Annapurna region guide compares every route here if you are still choosing.