From early-morning chairlift rides to high-output alpine ascents, base layers are the foundation of an effective cold-weather kit, helping manage moisture levels and warmth before you add insulation or a protective outer layer. Different styles offer different levels of coverage and temperature control.

For high-output days, a fitted top that moves moisture quickly can help you stay dry as effort levels rise. In colder conditions, base layer bottoms add warmth beneath outdoor trousers without unnecessary bulk. Hooded and zip-neck base tops give extra coverage and ventilation around the head and neck, letting you seal in warmth or dump heat on the go.

Choosing between base layers and thermals

In short, all thermals are base layers, but not all base layers are thermals. Both are worn next to the skin, but while thermals prioritise insulation for warmth, synthetic base layers are designed primarily to wick away sweat, preventing you from cooling down too quickly when you stop moving. Thermals are therefore suitable for lower-intensity days where you know you’ll be outside for a long time. Choose a moisture-managing base layer when you need extra coverage during high-output, cold-weather activities like ski touring.

Merino wool blends provide natural softness and warmth, for comfort during long, cold days outside. High-stretch synthetic fabrics dry quickly for efficient performance. Our Torrent™ stretch fleece sits between the two: it manages moisture, adds lightweight warmth and feels soft against the skin.

Fitted, low-profile designs sit close enough to the skin to wick away sweat effectively and layer cleanly under fleece, shells or insulated pieces. Both men’s and women’s base layers should move with you to avoid riding up or bunching beneath the rest of your outdoor clothing.

Frequently asked questions about base layers

Are base layers better than thermals?

That depends on whether you’re looking for softness and warmth for extreme cold or sweat-wicking performance for high-output activities. If it’s the former, look for merino wool thermals that trap heat; if it’s the latter, look for a quick-drying synthetic base layer.

What should you wear as a base layer?

The best base layer depends on the conditions and your activity level. On mild days, a long- or short-sleeved outdoor T-shirt on its own is fine. For cold-weather, high-output hiking, touring or climbing, choose a close-fitting top made from high-stretch, moisture-wicking fabric to keep you dry and comfortable.

What is the best base layer for winter?

A winter base layer should provide warmth without trapping excess moisture. A merino wool blend balances breathability and insulation, as well as natural odour resistance. If you’re trail running year-round, layer lightweight base-layer bottoms under your outdoor shorts or skirt for added coverage without sacrificing freedom of movement.