The Best Thermal Underwear and Base Layers for Women

Published on 01/04/2023 · 6 min readSnowboard Expert Kate Wilson details the do's and dont's of what to look for in baselayers, and lists some of her favorite baselayer options for women!
Kate Wilson, Snowboarding Expert
By Snowboarding Expert Kate Wilson

Photo by Anna Shvets

Planning the annual ski trip? Sledding with the kiddos, or first-time snowboarding? It's that time of year again, and making sure you're equipped with everything you need to stay toasty and warm outside is key to an awesome adventure.

While quality footwear and waterproof clothing are essential, some overlook the importance of the underlayers that will help keep you warm and dry during strenuous outdoor activities. Learning to identify the key components of cold-weather clothing will go a long way in staying comfortable outside this winter, no matter the temps!

Layering 101

A quick internet search on “winter sports apparel” will land you endless tips on layering, which is a buzzword used pretty much everywhere when talking about staying warm during cold-weather activities. Simply put, a waterproof outer layer, or “shell”, keeps moisture away, an insulated midlayer is instrumental for warmth, and a quality base layer helps with both!

In fact, your base layer is an extremely important consideration because it's directly touching your skin, and the right materials help manage moisture while maintaining natural body heat. Sadly, jeans or pajamas don't make the grade anymore. Even cotton gets a thumbs down for intense cold-weather activities since it does not wick moisture away from your skin—it actually fills up air pockets with sweat and causes rapid insulation loss. I made this mistake my first few times out several years ago and quickly did some research for a better option!


So what should you be looking for when purchasing base layers or thermal apparel? Here is a quick guide:

Infogram designed by Kate Wilson


Just the mention of this word brings unpleasant memories of sweaters from grandma back in the day. It's time to revisit this classic, sustainable material. The ultra-fine fibers of Merino wool offer comfort and a modern slim fit that is surprisingly flattering. It also has excellent breathability, wicks moisture away from the skin, and is a top choice for naturally occurring odor resistance. Another benefit is that it not only keeps you warm in cold weather but cool on hikes from spring to fall, too, with its natural body temperature regulating properties.

Expert Pick: Smartwool Women’s Classic Thermal Merino Base Layer Crew

I received this top as a gift almost five years ago and have worn it countless times on the mountain and even running errands as my regular shirt in cooler temps. It’s incredibly comfortable, lightweight, and stylish!

One reason for the noticeable comfort of Smartwool Merino is that their base layers feature flatlock seam construction, which helps minimize chafing and irritation—a huge consideration when these pieces are under multiple layers of clothing. The Smartwool Women’s Classic Thermal Merino Baselayer Bottom is an excellent compliment to the top above, each made with 100% Merino wool and an interlock knit for effective thermoregulation.

Blending other materials with wool is beneficial, too. The Icebreaker Women’s 150 Zone Long Sleeve Baselayer Shirt adds nylon and lycra for a flexible fit, and its mesh panels accelerate ventilation for maximum dryness. Gusseted underarms for mobility, a drop tail hem for added coverage, and a range of light, mid, and heavyweight options make the Icebreaker another solid choice!


Although I just sang the praises of Merino wool, there are reasons to consider alternatives. Occasionally, I will chat with a customer that is allergic to wool, or someone who is looking for a more affordable option. Synthetic fibers and fabrics like polyester and nylon offer exceptional sweat absorption and drying time, with high ratings for durability, too. The clothing itself is lightweight for the warmth it offers and, as alluded to above, it is typically less expensive than 100% wool. The downside? Synthetic blends do not resist odor as well as wool, and can be less insulating if they do get wet.

Expert Pick: Burton Women’s Midweight Base Layer Long Neck Shirt

The built-in neck gaiter on this shirt is such an awesome addition, like an upgraded warm and stylish turtleneck! It’s also pretty effective at odor control and uses Bluesign-approved materials, which means only safe chemicals are used to reduce impact on humans and the environment. Win! The Midweight Baselayer Pants pair perfectly with this shirt.

The Flylow Women’s Sondra Fleece is another Bluesign-approved midlayer with a gaiter-compatible funnel neck, longer length, and zippered chest pocket to keep your hot cocoa money safe on the mountain. Stylish enough to show off at the lodge drinking said cocoa, too!

If you’re looking for something with a little personality, the Obermeyer Women’s Discover Tights or Women’s Discover Crew fit the bill! All the same great blended synthetic tech but with colorful, fun patterns, flat seam construction, and an extra-flexible yoga waistband on the pants for added comfort. These just may end up being your best leggings ever since they can double as loungewear on or off the mountain.


While not as popular as wool or synthetic blends, silk is gaining popularity. It compacts down extremely small for packing, absorbs up to 30% of its own weight in moisture, dries quickly, and wicks moisture away from the skin. It goes without saying this fabric is (silky) smooth and comfortable, too.

Recommended for low-intensity activity and priced the highest of the three options, silk is one to keep in mind if you’re looking for a lightweight, extremely comfortable option. Terrama’s 1.0 Thermasilk Heritage Pant fits the bill with a stretchy waistband, natural thermoregulation tech and ultra-light materials keep you warm without the bulk. Their pieces are made from 100% filament silk, and each piece is machine-washable, too!

Choosing a Layer

Once you've determined which material is best for your budget or personal preference, choosing between light, mid, or heavyweight options is next. Weather and anticipated activity level come into play here: lightweight pants and tops make a great base layer for milder temps, or if you heat up easily. Midweight is just that, an option between light and heavy that is suitable for most. While heavyweight caters to the colder climate or those who need all the help they can get to stay warm. Some argue that a lighter weight base is optimal, and adding bulk with a thicker mid layer since thinner materials are quicker to dry and more breathable.

Finally, be sure that each piece closest to your skin is form-fitting, or “snug”. A fabric’s ability to wick moisture away quickly is compromised if it’s not right up against your skin, and loose-fitting thermals allow cold air to move around your body, no matter how much you have layered over them. Choosing quality base layers is just as important as your insulated coat, outer shell, accessories, and even the sporting gear, because staying comfortable outdoors is what will keep you heading out again and again!

Reach Out

Have questions about which base layers are best for you? Connect with one of the Experts here at Curated for personalized recommendations and advice! We are here to make sure you have all the gear you need for your adventures this year and would love to hear your feedback on base layers you’ve tried in the past!

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Have a question about the article you just read or want personal recommendations? Connect with a Curated expert and get free recommendations for whatever you’re looking for!

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Smartwool Women's Classic Thermal Merino Baselayer Crew
Burton Women's Midweight Baselayer Long Neck Shirt
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Icebreaker Women's 150 Zone Long Sleeve Baselayer Shirt
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