Getting the forecast…
Hour by hour, the cloud base and the freezing level are in the TrailSync app.
Forecast: Open-Meteo (CC BY 4.0). Wind is for the hill's area at 10 m above the ground; on the tops it can be stronger.
Ben Nevis by its finest walkers' line: a long, sustained climb to Càrn Mòr Dearg, then the arête — a short, airy ridge of rocky slabs and boulders — before a steep, tiring pull onto the roof of Britain and the long descent by the Mountain Track. Exposed but never extreme; a big day that rewards steady pacing.
Good path to CMD; the arête is rocky slabs and boulders with a clear line through, round and over them; loose scree off the Nevis summit easing to a well-made path; the return from the halfway lochan is intermittently pathless and wet, with a minor river crossing.
Forestry track then a good path climbs steadily south into the glen of the Allt a' Mhuilinn, the north face of Ben Nevis filling the view ahead. Ground is straightforward and well walked. Save your legs — the day is long and the real work is still to come.
Leave the glen path and climb the broad slopes towards Càrn Dearg Meadhonach and on to Càrn Mòr Dearg (1,220 m). It is a sustained pull — nearly 700 m in three kilometres — but the path is clear and the ground turns from grass to rock as you gain height, drying underfoot. In winter this ground was frozen; in summer expect it wet lower down. The summit of CMD is where the day changes: the arête curls away in front of you towards Nevis.
You are on the arête within minutes of leaving CMD's summit. It looks far worse from the summit, and worse again on the wide-angle footage people post, than it is underfoot: there is exposure, but you are never over an edge, and there is no involved scrambling. A clear line moves through, round and over rocky slabs and boulders, dropping about 180 m to the col. A few hands-on-rock moments are more for your own peace of mind than necessity. Roughly a kilometre long — as long as it takes you to move a kilometre carefully. If heights unsettle you it can feel daunting; take your time. Winter: a Grade I route.
Exposure. A ridge of slabs and boulders — take it at whatever pace keeps you safest.
From the col the hardest part of the day: a steep 300 m climb up boulder-field onto the summit plateau. It is less about difficulty than about how much you have left in the legs — clambering over boulders on the way up, then the plateau opens and the summit shelter, cairn and trig point of Ben Nevis (1,345 m) are yours.
Steep, loose, tiring — the effort crux of the day.
Leaving the plateau is the serious navigational moment of the day: in poor visibility use the marked bearings — 231° for 150 m from the trig point, then 282° — to avoid the gullies on the north side and the steep ground of Five Finger Gully. Once onto the Mountain Track there is a stretch of loose scree off the summit that soon eases into a stable, well-made path down the zig-zags to the halfway lochan (Lochan Meall an t-Suidhe).
Summit plateau navigation in cloud — the classic bearings matter (231° for 150 m from the trig, then 282°) to stay clear of Gardyloo and Five Finger gullies.
Leave the Mountain Track near the lochan and cut back towards the Allt a' Mhuilinn. This is the least defined ground of the day: the path comes and goes through wet ground, though never for long, and needs a little route-finding. Cross the Allt a' Mhuilinn — multiple paths lead to multiple crossings and the one on the line is easy — then rejoin the glen path from stage 1 for the walk out to the North Face car park.
Minor river crossing — mind it in spate or after snowmelt / heavy rain.
If you need to turn back: From the arête, retreat back over CMD is the safest option; there is no easy descent from the col itself. From the summit, the Mountain Track is the descent in all conditions.
One of my best days on the hills — one I'll do again and again. — Robert, walked 30 Nov 2025 in winter conditions.