What to wear under ski pants, and what to leave at home

Why the lower half gets neglected

The top half of a ski outfit is a conversation: base, mid, shell, and everybody has an opinion. The bottom half is two garments and gets about four seconds of thought, usually on the morning of, usually in a hotel room.

That is a mistake for a specific reason. Your legs are doing most of the physical work of skiing, so they produce most of the sweat, and they are also the part sitting directly on a cold chairlift for a quarter of the day. Get the top half wrong and you are uncomfortable. Get the bottom half wrong and you are wet, then cold, then finished.

The system, which is two things

One pair of base layer bottoms

Wool or synthetic, midweight, full length. The published figure to shop on is fabric weight in grams per square meter, which is the only number that means the same thing across brands. The MERIWOOL layer in this ledger publishes 250 gsm, which is the midweight band and the right default for someone who alternates between working hard and sitting on a lift.

Midweight is genuinely the answer for most people. Lightweight suits someone who runs hot or skis in spring; heavyweight is usually too much under an insulated snow pant and adds bulk where a boot cuff already sits. The base layer page covers the material argument in full and it applies unchanged to legs.

One thin ski sock, over the base layer

The sock goes over the base layer bottoms, not under them, and it should be a single thin over-the-calf ski sock. Both socks in this ledger publish lifetime terms - one unconditional, one limited - which makes them among the cheapest durable things on the site.

The counterintuitive part: thin, not thick. A thick sock fills space in a ski boot that should be filled by your foot, which both loosens the fit and makes the boot colder by restricting circulation. The sock page makes the full argument.

The four things that should never go under snow pants

Cotton is the one that ruins trips, and it is worth being blunt about because it is also the cheapest thing to fix. The what-not-to-wear page covers the rest of the outfit in the same spirit.

The same weight bands apply top and bottom. The base layer roundup sets out what 150, 190 and 250 g/m² are each for, and which fiber suits how you ski - the decision is identical for legs.

How many layers the legs need

One, in almost every condition. Snow pants - insulated or shell - are already cut with room for a single base layer, and legs generate a great deal of heat once you are moving. Two layers under a fitted snow pant compresses both and squeezes out the trapped air that was doing the insulating, which is the same physics as the mid-layer page describes for the torso.

The exceptions are narrow and real: a genuinely severe day, standing still for hours watching a lesson, or a shell pant with no insulation of its own. In those cases a heavier single base layer beats two thin ones, because it does not compress.

If you are still cold with a correct base layer, the cause is usually not the legs. The temperature bands page works through what actually changes as it gets colder, and the answer is almost always exposure and extremities rather than torso or leg insulation.

The boot cuff detail nobody mentions

Everything below the knee is inside a rigid plastic shell for the whole day, and anything bunched in there becomes a pressure point. Three checks before the boot goes on:

• Base layer smooth, no folds at the calf. Pull it taut before the sock.
• Sock pulled over the calf, above the top of the boot. Bare skin against a boot cuff is where shin bang and rubbing start.
• Snow pant cuff outside the boot, not tucked in. The internal gaiter goes over the boot; tucked inside, it funnels snow straight in. Which is one more argument for bibs.

If a boot still hurts after all of that, it is a fit problem rather than a layering one, and a footbed is often the cheapest fix.

Children

Same rules, applied more carefully, because a child will put on whatever is nearest and will not mention that their legs are wet until they are miserable. Buy the base layer as a set - top and bottoms - rather than a top plus whatever was in the drawer.

The kids base layer roundup covers the published weights, and the kids layering page has the physical checks that beat asking them how they feel.

The whole thing, in one line

Base layer bottoms in wool or synthetic, midweight, full length. One thin ski sock pulled over the top and smoothed flat. Snow pant cuff over the boot. Nothing cotton anywhere, and nothing doubled up.

That is a two-item list that costs less than a lift ticket and fixes the most common way a first ski day goes cold. It is also near the front of the buying order, for exactly that reason.