Winter hikers get cold for two opposite reasons: too little insulation when they stop, and too much sweat while they climb, which then chills them at rest.

The classic system solves this with three adjustable layers: a snug synthetic or merino base layer that moves sweat away from skin, a fleece or insulated mid-layer for warmth, and a windproof or waterproof shell.

Add a warm hat, gloves, neck gaiter and insulated boots, and always carry a spare dry base layer and an extra insulated jacket for stops and emergencies.

The key habit is to start slightly cold, vent or remove a layer before you sweat, and put the warm layer back on the moment you stop moving.