What do you wear under ski pants and a ski jacket?
Last updated: October 2026 · By Slope Goons
Wear a moisture-wicking thermal base layer under both ski pants and your ski jacket. For temperatures below -5°C, add a fleece or thin down mid-layer between your base and jacket. Never wear cotton — it absorbs sweat, stays wet, and makes you cold. A good base layer is the most important piece of your ski kit after the outerwear itself.
The base layer: the most important undergarment
A base layer sits directly against your skin. Its job is to wick moisture (sweat) away from your body and transfer it to the outer layers where it can evaporate. Without a good base layer, sweat builds up against your skin, makes you damp, and then cold.
Good base layer materials: merino wool, polyester, nylon. Bad base layer material: cotton. Cotton holds moisture and loses insulating ability when wet.
The mid-layer: optional but useful
The mid-layer goes between your base and your jacket. For most resort skiing with an insulated jacket, a mid-layer under the jacket is optional. You need one when: you're wearing a shell jacket, temperatures are below -5°C, or you feel cold even in an insulated jacket.
Good mid-layer options: fleece pullover (warmth + breathability), thin down gilet (packable warmth, no arm bulk), synthetic insulated jacket (warmth even when damp).
Layering comparison by temperature
| Temperature | Under jacket | Under pants |
|---|---|---|
| Above 0°C | Light base layer only | Light thermal base layer |
| 0°C to -5°C | Thermal base layer | Mid-weight thermal base layer |
| -5°C to -10°C | Base + fleece or thin down | Thermal base + thin mid |
| Below -10°C | Base + insulated mid-layer | Thermal base + thick mid |
What never to wear underneath
Avoid cotton in any layer when skiing. Jeans under ski pants, a cotton T-shirt under a jacket, or a cotton hoodie as a mid-layer — all are mistakes that will make you cold and miserable within a few hours of active skiing. Even on warm spring days, a light synthetic base layer beats a cotton shirt.
Which Slope Goons product is right for you?
- LegoFace Ski Mask — the face-layer that completes your base-to-shell system with full wind protection
- Frosty Face Ski Mask — think of fleece face coverage as a mid-layer for your face on cold days
- The Slope Stitches Balaclava — covers head and neck like a base layer for your skull, keeping the warmth in where it matters
Frequently asked questions
Can I wear normal clothes under ski pants?
You can, but it's not ideal. Regular trousers or jeans absorb moisture and get cold. A thermal base layer under ski pants keeps you drier, warmer, and more comfortable all day.
Do I need a mid-layer under my ski jacket?
For most ski days (0°C to -5°C), a thermal base layer plus an insulated ski jacket is enough. Below -5°C or in a shell jacket, add a fleece or down mid-layer for extra warmth.
Should thermal base layers be tight or loose?
Thermal base layers should be close-fitting — not tight, but no excess fabric. A snug fit maximizes moisture-wicking contact with your skin and keeps warmth trapped efficiently.
Is merino wool or synthetic better for ski base layers?
Merino wool regulates temperature better and stays odor-free longer, making it great for multi-day trips. Synthetic base layers dry faster and cost less. Both work well on the slopes.