Last updated on November 3rd, 2023 at 11:34 am
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Not all base layers will fit all conditions.
There is a big difference in temperature between going skiing at the beginning of January or in mid-April. And there’s an even bigger difference in temperature between going skiing in cold Trysil in Norway and going skiing in sunny Serre Chevalier in France.
So, I thought I would make a short guide to base layers for different conditions and include some trusted recommendations.
The base layer is the clothing you put on first before you put on the mid-layer, outer shell, and ski pants.
It’s thermal underwear, made from breathable material, designed to keep your body warm on cold days in various outdoor activities – from backcountry skiing to skiing down the pistes.
Thermal base layers usually consist of a top and pants. However, you can also get one-piece (or onesies) base layers. They are just not as common, and they can be a bit of a hassle when you have to visit the toilet.
Base layers are designed to wick away sweat from your body. When you stay dry, you stay warm.
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What is the wicking effect?
The wicking effect refers to the ability of a fabric or material to draw moisture away from the body through capillary action.
In other words, it is the process of moisture movement through a fabric, which helps to keep the user dry and comfortable and preserve body heat.
A good base layer will always wick moisture away from your body.
Avoid cotton at any cost! Even though cotton is warm, it will absorb and hold onto moisture instead of wicking it away.
In cold temperatures, the wet cotton will get cooled and, as a result, cool your body temperature, which can be dangerous.
What are base layers made from?
Recommended base layers for skiing are made from synthetic materials or merino wool.
It is not uncommon to see base layers (even those made with merino wool) made from a blend of different materials.
Both types of base layers have pros and cons. They also work in different ways, which I’ll describe below.
About Base Layers Made From Synthetic Fibers
Base layers made from synthetic materials are lightweight, good at wicking away sweat, and quick drying. They are often made from a hybrid of polyamide, polyester, nylon, elastane, or similar materials.
Compared to wool, they offer little odor control (they tend to stink after long days on the mountain!). They are also slower when it comes to regulating temperature.
I’ve found that cheaper base layers have a terrible fit and tend to shrink when machine-washed (which ruins the fit even further). In my experience, they also tend to get itchy and become static.
Synthetic base layers are often cheaper than base layers made from wool. And they can be a great option for warmer days.
About Merino Wool Base Layers
Ski base layers made from merino wool are lightweight, offer excellent odor protection, and are soft on the skin. And they’re the best option for cold weather.
Merino wool is grown by merino sheep, which live in icy conditions in New Zealand and is thinner and softer than regular wool.
The reason merino wool doesn’t stink is that of the lanolin and keratin wax in the wool, which sheep naturally produce. These give the merino wool antibacterial properties, which makes it possible to wear a merino wool base layer for a whole week of skiing without the need for washing.
Merino base layers have excellent moisture control
Merino wool doesn’t have the same wicking abilities as synthetic materials. Instead, merino wool relies on absorbing sweat, but it does so while maintaining its breathability and core body temperature regulation abilities at the same time (as opposed to cotton).
Merino wool fibers are porous and trap moisture vapor inside.
Synthetic fabrics transport sweat as a liquid, meaning your body has to heat it to evaporate it, making you feel clammy.
Merino wool skips this step by trapping the moisture when it is still vapored.
Merino wool can trap up to 30% of its weight in moisture and still feel dry on your skin.
Merino wool has a natural insulating effect because the wool will crimp and trap dead air, which acts as a buffer against the cold.
As your body temperature rises, the moisture trapped within the merino wool fibers will evaporate, and the dead air will start to cool. It is because of this that merino wool is so good at keeping you warm and dry at the same time.
And the thicker or more heavy-weight (more on that in a moment) a base layer you choose, the worse the wicking abilities become.
Merino wool additional features
Merino wool also provides natural UV protection.
Merino wool baselayers are made from sustainable materials and are biodegradable.
Base layers made from merino wool are more expensive than base layers made from synthetic materials, though. And they are also heavier.
Merino wool doesn’t itch!
I must admit that I had doubts when I first heard of merino wool. My prior experience with wool up to that point had been that it was itchy, warm, and uncomfortable to wear against bare skin.
But merino wool is none of those things. It doesn’t itch, and it is very soft on the skin. I also love the fact that it doesn’t stink after a day of skiing.
Because of these advantages, I find Merino wool and merino wool blends to be the best materials for baselayers these days.
Base layers and weight classes
Base layers for skiing are usually classified into three weight classes: lightweight, mid-weight, and heavyweight. The weight classes are measured in grams/m2 fabric weight. The higher the number of grams per square meter, the warmer the base layer is.
Lightweight insulation usually ranges from 170-200 grams. These are good at the end of the season in Marts or April when it is balmy. If you pair them with a warm mid-layer, softshell, or 3-in-1 jacket, you can also wear them earlier in the season. I would not recommend these for cold or icy conditions, though.
Mid-weight insulation usually ranges from 200-300 grams. This weight class is the most versatile when it comes to recreational skiing. When I go skiing in the Alps early or mid-season, this is the base layer weight class I usually bring.
Heavyweight insulation is anything from 300 grams and up. These are the warmest base layers. If I go skiing in Norway or Sweden in the early or mid-season, this is the type of base layers I’ll bring, as they are the best choice if you need that extra warmth.
Heavyweight insulation is sometimes worn as an extra layer of insulation on top of, e.g., a lightweight base layer.
How should a ski base layer fit?
The base layer must have a tight fit/slim fit against your skin.
A base layer has to lay against your body to pick up moisture and wick it away from your body and into the mid layer and shell.
If the base layer is too loose, it won’t be able to transfer the moisture away from your skin to the outer layer.
Some base layer tops come with a high neck – or turtle neck – for a bit of extra warmth on frigid days.
Whether you need this or not is a matter of personal preference. I’m not fond of the turtle neck design and prefer to bring a fleece neck warmer instead.
A quick tip on base layer pants
When you’re shopping for base-layer pants, don’t look for the full-length version. Instead, see if you can find a 3/4-length version that matches the base layer top.
You don’t want the pants to go into the ski boots because that can cause a lot of sore skin from chafing, and they’ll conflict with your ski socks. And baselayers are usually so tight that you can’t pull them up over your calf.
I love 3/4-length base-layer pants because they stop above the ski boots.
Best base layers for skiing
So let’s have a look at some brands of base layers, that I trust to do the job of keeping me warm on the slopes.
When possible, I’ve included the pants as well.
SmartWools Baselayers are made from 100% merino wool. It has flatlock seams, which eliminates chafing.
I especially like the length of the arms on this one, since a lot of athletic fits tops, I’ve tried, have suffered from being too short in the arms. I haven’t had this problem with this one.
Good SmartWool tops for women:
Smartwool Women’s Merino 150 Baselayer Long Sleeve
Smartwool Women’s Standard Merino 150 Base Layer 1/4 Zip
Smartwool Women’s Merino 250 Baselayer Crew
Smartwool Women’s Base Layer Top – Merino 250 Wool Active 1/4 Zip
Good SmartWool bottoms for women:
Smartwool Women’s Merino 250 Base Layer 3/4 Bottoms
Good SmartWool tops for men:
Smartwool Merino 150 Base Layer Long Sleeve
Smartwool Men’s Merino 150 Base Layer 1/4 Zip
Smartwool Standard Merino 250 Base Layer Crew
Smartwool Men’s Standard Merino 250 Base Layer 1/4 Zip
Good SmartWool bottoms for men:
Smartwool Men’s Merino 250 Base Layer 3/4
Another brand I trust to keep me warm is Icebreaker. The Icebreaker Merino Oasis Midweight Base Layer is made from 100% merino wool at 200g/m2. Thus it is a bit lighter and cooler than the SmartWool mentioned above. I would still classify it as a mid-weight mid-season base layer for most – except the very cold – resorts.
If you have a warm mid-layer or insulated jacket, and you find the 250g option a tad to warm, this might be what you’re looking for instead. This specific model comes with a zip neck collar for temperature regulation and flatlock seams. It also has nice long sleeves which goes nicely together with the athletic fit.
Good Icebreaker Base Layer set for women:
Icebreaker Merino Women’s 200 Oasis Long Sleeve Crewe Top T-Shirt
Icebreaker Merino Women’s 200 Oasis Cold Weather 3/4 Leggings
Good Icebreaker Base Layer set for men:
Icebreaker Merino Men’s 200 Oasis Long Sleeve Crew Shirt
Another brand, I recommend you check out is Kari Traa, which makes some really nice base layers for women. Unfortunately, I don’t think the make 3/4-length bottoms yet, but their tops are really nice!
If you need heavyweight base layers, I recommend you look at brands such as WoolPower and ACLIMA.
These base layer is made from merino wool at 400g/m2 and is an excellent choice when the temperature reaches temperatures between -20 to -30 degrees Celsius (-4 to -22 degrees Fahrenheit).
Helly Hansen is another brand, that I trust, and the
This particular base layer is the light weight version, which is excellent as a late season base layer, or a mid-season base layer combined with a good insulating mid-layer or ski jacket.
The Helly Hansen Lifa Stripe series is a synthetic base layer top made from polypropylene. It has excellent wicking properties and best of all, I don’t find it itchy like some of the cheaper alternatives on the market.
Men’s Helly Hansen Lifa Stripe Crew Neck baselayer
Men’s Helly Hansen Lifa Stripe 3/4 length baselayer pants
Women’s Helly Hansen Lifa Stripe Crew Neck baselayer
Women’s Helly Hansen Lifa Stripe 3/4 length baselayer pants
Closing Comments
I hope you’ll find this helpful information when shopping for your next base layer.
It probably should be no surprise that my top picks these days are base layers made from Merino wool. The soft fabric, natural fibers, and snug fit make them a great base layer for intense activity in cold conditions during the winter season.
I also have base layers made from synthetic fibers or a Merino wool blend (the next best thing), but if I need to stay warm, I always go with Merino.
What is your favorite brand of base layers, and why? If you have a good tip for an excellent base layer, please share in the comments.
Happy skiing, and keep warm and dry.
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