How to Choose Ski Base Layers & Long Underwear

Buying Guide  Gift Cards

We have one of the largest selections of long underwear and ski base layers on the web, a super knowledgable staff and expert guides to help you make an informed decision.

What is a base layer and why do you need to wear one?
A base layer is an insulating layer worn next to your skin. Base layers help regulate your body temperature by moving perspiration away from your skin, which will help keep your dry. Staying dry allows you to stay warm and happy in the winter. Base layers come in many forms from T-shirts to tights to briefs and sports bras. Some are designed to contour to your body while others are loose fitting. Base layers come in different weights or thicknesses to suit different temperatures and activity levels.
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In buying a base layer, you will want to consider:

Base Layer Weights
Generally, there are three different base layer weights.

This is a thin first layer that goes next to your skin with the ability to easily add layers over it. Lightweight base layers are a crucial step in layering as they must be comfortable on the skin and are designed to fit tighter for the best moisture management. Worn alone they are best suited for mild to cool conditions with high levels of activity like running, climbing, cross-country skiing, etc.
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A midweight layer can be worn as a warmer first layer or as a second layer over your next-to-skin layer, providing a combination of insulation and moisture wicking. Alone it is best suited to cool or moderately cold to cold conditions with medium levels of activity where you will be moving some of the time but standing still at others. It can be combined with lightweight layers underneath or heavyweight layers over it to accomplish the desired warmth.
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This is designed for cold conditions combined with any level of activity and often referred to as "expedition weight". Almost always worn over a lighter weight layer, heavyweight layers are designed to add insulation and are worn looser without as much focus on moisture management. These layers are thicker due to their higher loft for insulation.
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The majority of base layers in today’s world are composed of either Merino wool or synthetic fabrics like Polypropylene. Rather than absorbing moisture, these fabrics wick (transport) moisture and perspiration away from the skin and disperse it on the outer surface where it evaporates. Both of these fabrics do roughly the same things: efficiently transport moisture away from skin, dry much faster than conventional cotton underwear and reduce the risk of dramatic swings in body temperature.
Synthetic vs. Wool
Synthetic Wool
The Good
  • Soft
  • Easy care
  • Lightest base layer
  • Abrasion-resistant
  • Wrinkle-resistant
  • Very stretchable
  • Excellent moisture management
  • Excellent drying time
  • Fairly priced
  • Soft to skin lightweight fabric
  • Stain and wrinkle resistant
  • Natural fiber
  • Excellent moisture management
  • Excellent temperature regulation
  • Excellent odor resistance (it doesn’t stink)
  • Very good stretch
The Bad
  • Slightly slower temperature regulation than wool
  • Synthetic fiber
  • Odor can build up if not consistently washed
  • Petroleum-based synthetic fiber
  • Potentially vulnerable to staining
  • Slower drying time than synthetics
  • Potentially vulnerable to shrinkage if not washed properly
  • More expensive than synthetic base layers

Types of Base Layers

Long Sleeve - Long sleeve base layers are generally used in colder conditions under additional layers in order to maximize warmth.

Under Armour Base 3.0 Crew Top - Women's

Short Sleeve - Short sleeve base layers tend to be used in hot to warm to cool conditions where moisture wicking is more important than heat retention and wearing just a short sleeve base layer won’t make you freeze. 

Smartwool NTS Micro 150 Pattern Tee

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Long Leg - Long leg base layers are generally used in colder conditions and generally as a part of a set of layers. Snowboarding, skiing, alpine hiking, riding in cold weather are all examples of activities that need a long leg base layer.

Helly Hansen Active Flow Pants

Three Quarter Leg - ¾ leg base layers are generally used for skiing and snowboarding. They stay out of the ski boot or snowboard boot therefore eliminating discomfort.

Armada Contra 3/4 Pants
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One-piece - One piece base layers are the ultimate in base layer protection. They seal out any drafts and cover the majority of your body, making for a perfect base layer in cold conditions. Some one piece base layers even have a hood because 40% of your body heat can “escape” through your head.

Airblaster Merino Ninja Suit

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All base layers are designed to perform whether worn alone or with other layers.

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Learn more with our other Outerwear Guides:
Waterproof Ratings & Breathability Guide
Outerwear – Fit Guide & Jacket Length
Outerwear – How to Choose by Region
Insulated Garments – How to Choose
GORE-TEX® Fabric – How it Works & Product Testing
GORE-TEX® Fabric – How to Wash & Keep Waterproof
Backcountry – How to Dress

This is evo. We are a ski, snowboard, wake, skate and clothing online retailer with physical stores in Seattle and Portland. Our goal is to provide you with great information to make your purchase easy.

Still have questions? Please give our customer care team a call at 866-386-1590, Customer Care Hours. They can help you find the right base layer to fit your needs.