Warmest Base Layer: Staying Warm in the Winter Weather

A man wearing an Patagonia Outlet
Written by Kane Dane

It is definitely overwhelming to choose the warmest base layer when it comes to brand and price. The base layer is the groundwork for the rest of your layers when you are going out to enjoy some winter activities like hiking or Snowshoeing. The best base layer for cold weather is the best because it fits your skin closely and allows you movement to enjoy activities.

While you may look for something eye catching, remember the purpose is to keep you warm and dry. Try to look for base layers that will not irritate your skin or make you sweat or hold onto moisture.

Three skiiors wearing base layers

Having a list of products can be helpful because you can find so much information in one spot on exactly what you are looking for. We will discuss the best base layers available on the market and give you all of the details so you can choose which is the best base layer for cold weather that will fit your lifestyle, as well as give you tips and ideas on base layers.

Our Top Picks

Product NameWeightBest UseSpecial FeaturesPrice
REI Midweight Half-Zip180 gramsAny sportFlat seams, long sleeves and a zipper, dries fast, spandex and polyester materials, high UPF rating.    Check price on REI    
REI Midweight Crew175 gramsSkiing89% polyester and 11% spandex, polyester wick, tall neck, chin guard, long sleeves and zipper.    Check price on REI    
Icebreaker Zone260 gramsSkiing and hiking96% wool and 4% elastin, wool, nylon and elastin on the eyelet of the base layer, made to fit on a female body and has zip neck flat seams.Check price on Amazon
REI Lightweight Half-Zip175 gramsMulti sportPolyester that is very soft, a zipper that has a guard for the chin, flat seams, gussets and raglan sleeves, longer back end, UPF 30.    Check price on REI    
Smartwool NP225113 gramsMulti sport, everyday useAll Merino wool interlocked, form fitting and comfortable on the skin, made with the best moisture management system on the market.Check price on Amazon
Smartwool 0SS603340 gramsSkiingAll Merino wool, with interlocking weaves, and zipper, shoulder panels, and flat seams.Check price on Amazon

Features to Consider Before Buying

We will now discuss the four types of base layers, the various weights of them, and will help you learn how to choose the right base layers for the weather you have, among other factors to consider.

Types Of Base Layers

Synthetic: The majority if base layers are synthetic or wool, which also include polyester and other material to help keep your base layer flexible and warm. However, synthetic base layers do not breathe well and are not quite as warm as other material. Plus, it will hold in odors more than others.

Merino Wool: This is good for cool or cold weather and allows you to exercise easily and stay warm. Even on warmer days, this material is great to wear. Base layers made from wool with fleece keeps skin protected from the cold conditions as well as the sun.


Silk: This is a great material for colder climates and for those who enjoy winter activities and exercises that do not involve a lot of movement. Silk base layers wick away sweat and moisture and keeps it away from the skin. Silk can get smelly, so wash it after each time you wear it, and it cannot protect your skin from sun damage.

Bamboo: Using bamboo as a base layer is a fairly new idea, but when it is joined with cotton, fleece or even Lycra, it can be just as good as a wool base layer, and it will keep its shape over time. Using a bamboo base layer is better for people who dislike the feeling of wool.

Weights Of Base Layers

Light weight: When choosing a light weight base layer, know that these are more for higher impact workouts and activities in warmer temperatures. They are generally cheaper in price and easier to put in your backpack than something bulkier.

Mid weight: This the most used type of weight for base layers and are generally used in the autumn or spring times. This is just a little bulkier than a light weight and just less bulky than an expedition weight base layer and it weighs twice as much as a lightweight base layer.

Two adults wearing base layers in the winter time

Expedition Weight: This type of base layer is the thickest and is used in cold and frigid weather and for more difficult activities in the winter. This type of the protective layer is way higher in price, but can keep you warmer than other types of base layers.


Warmth is the most important factor when choosing a base layer. Your base layer should provide warmth, but not allow you to sweat too much. You need to find balance. Use a less warm base layer if you are going to do a lot of exercise or if you find yourself in warmer temperatures.


While keeping warm is a must, your base layer should breathe, so that you do not build up a sweat.

A woman skiing on top of the moutanins

Your base layer should allow some water vapor to pass through it, which means it will go back into the air and your body will not be too affected by it.

Drying Speed

Nobody wants to be wet when they are outdoors, especially in cold weather. Your base layer will no doubt get wet at some point and knowing the time it will take to dry can help you in purchasing a new base layer. Do not forget, a wet base layer can make you feel really uncomfortable.


Because some base layers can be quite pricey, you will want to make sure the product you are purchasing will be durable, which means it will last a long time.

Two adults running wearing two base layers

Synthetic base layers will be very durable, whereas a wool base layer may not last as long.


Being comfortable and having the right fit of a base layer will ensure you have a great time outdoors. If it retains static, you can get shocked. Try on your base layer if possible, before you purchase it, so you can make sure it not only fits right, but will be comfortable when you are enjoying outdoor activities.

Top Base Layer Reviews

Not only are the features important, but you might want to consider the brand and the price as factors too. Below we came of with a list of the best reviewed base layers, so that you can take a look and judge the other aspects of each one before you make a choice.

REI Midweight Half-Zip REI Midweight

Price:  $50 – $60

Dimensions: 9 x 6 x 5 inches

Weight: 180 grams

Specific features: Flat seams, long sleeves and a zipper, dries fast, spandex and polyester materials, high UPF rating.

Best use: This base layer is best used for multi sport activities.

Description: The REI Midweight Half-Zip Base Layer will keep your body warm while wicking moisture to keep you dry. This product was designed for high amounts of performance while outdoors in the cold weather.

It is made of polyester and spandex, which will dry fast, plus it has UPF 50 protection from the sun, is fitted and has an extended hem that will stay tucked in your pants to keep you warmer. The sleeves are raglan so you will feel comfortable and have range of motion.

Tall neck extends coverage, protecting you from strong winds, or simply from the cold weather hitting your neck. It also has a UPF 50 sun protection. Normally people forget that even during cold weather the sun can affect your skin. Luckily most base layers come with such technologies, and this REI base layer is one of them. Feel free to wear for any sport, from hiking, to cycling or skiing, it will protect you from the uv rays.


  • UPF 50 protection to make sure your skin is safe
  • Midweight base layer, designed for high performance sports
  • Comfortable and durable


  • Some find it too loose, too baggy.

Related: Being a Multisport base layer, it is a good idea to buy alongside the Darn Tough Vermont Socks. This pair of socks is very warm and comfortable for winter hikes and other sports.

Check the price on REI

REI Midweight CrewREI Midweight Crew Top

Price: $45 – $60

Dimensions: 7 x 5 x 4 inches

Weight: 175 grams

Specific features: 89% polyester and 11% spandex, polyester wick, tall neck, chin guard, long sleeves and zipper.

Best use: This base layer is best used for skiing or multi sports.

Description: The REI Midweight Crew Top is a great value for your cash, as it has a lot of performance and function that comes with it. You can use this for casual wear as well as outdoor sports like Snowshoeing and hiking.

This base layer is extremely soft, but some say that wool can be softer. Otherwise, this is a must have piece in your winter gear collection because it wicks moisture, and the hemming on the shirt keeps your back covered if you bend over while in the cold. Also, this base layer is UPF 50 protection from the sun.

Unlike the REI Half Zip, the Crew Top is a fitted and less looser base layer. As a matter of fact, it is the definition of a base layer, as it fits perfectly your upper body for better comfort. It might have a bit of an issue with the breathability, as it can be too close to your body during high performance activities. However, it dries very quickly.


  • Fits really well
  • UPF 50 to protect your skin
  • Very warm


  • Breathability of the layer might be a bit of a problem

Related: The Arcteryx 5681 Beanie can be a good add on with this base layer. If you plan to stay warm whilst doing any winter sports, a beanies is a must have.

Check the price on REI

Icebreaker Zone Icebreaker Zone

Price: $45 – $120

Dimensions: 15 x 11 x 2 inches

Weight: 260 grams

Specific features: 96% wool and 4% elastin, wool, nylon and elastin on the eyelet of the base layer, made to fit on a female body and has zip neck flat seams.

Best use: This base layer is great for skiing and hiking.

Description: The main attraction of the Icebreaker Zone Top is the fleece inside and the ability for it to breathe so well. It can be great for not only skiing and hiking, but for cycling and various exercises.

There is 200g fleece inside and has a control temperature built in for quick changing weather. Not only will you stay warm, but your base layer will stay in place, and this is what people love about it. This is one of the most innovative base layers out there, this inner fleece really allows the users to feel comfortable under any circumstance. There is no risk of feeling asphyxiated after a long day of use, or if the temperature suddenly rises.

It was specifically designed for females, hence why it has such a good fit for them on top of a very stylish look. Reviewers have enjoyed the way the base layer looks on them even indoors.


  • Perfect fit for women
  • Stylish look
  • Inner fleece features make it ideal to wear under any circumstance
  • Very good breathability


  • Some reviewers said the fabric made their skin itchy

Related: The Icebreaker Rush Tights are a good add-on to buy with this product. They are warm enough for those days that aren’t too cold, you can wear them as sports outfit, otherwise, wear them as underpants to stay warm.

Check the price on Amazon

REI Lightweight Half-ZipREI Lightweight

Price: $35 – $50

Dimensions: 7 x 5 x 4 inches

Weight: 175 gram

Specific features: This product features polyester that is very soft, a zipper that has a guard for the chin, flat seams, gussets and raglan sleeves. It has a longer back end, and has a UPF 30 level of sun protection, plus it is fitted

Best use: Multi sport

Description: This REI Lightweight Half-Zip Base Layer will keep you warm and dry while you are exercising vigorously, even if the temperature changes. You can stretch easily in this base layer and will see that it can control wetness with ease.

This is perfect for days when you do not need a lot of insulation, but the temperature is still cool. Both of the inside and outside are designed to dry quickly, and it protects the skin against UV rays from the sun.

Like most of REI base layers it was designed with the purpose of doing sports whilst wearing it. That’s why it not only protects you against the sun, but it has a very good breathability and provides a lot of comfort. This particular model has a longer back hem so that whenever you move or lean forward, it stays tucked in. Also, it’s made of a soft polyester material that dries very quickly.


  • Out of REI’s models, probably the most comfortable one
  • Breathability is really good


  • Being a lightweight base layer, it doesn’t provide as much warmth on very cold days

Related: The Smartwool NP605 Bottoms are a good idea to buy alongside any base layer. They provide the same features and protection but for the legs.

Check the price on REI

Smartwool NP225 Smartwool NP225

Price: $85 – $105

Dimensions: 12 x 8 x 2 inches

Weight: 113 grams

Specific features: All Merino wool interlocked, form fitting and comfortable on the skin, made with the best moisture management system on the market.

Best use: Multi sport

Description: Smartwool NP225 Bottom is perfect for the intense cold weather and winter activities. Your body will have range of motion and the ability to do most winter sports and exercise with ease and comfort.

They stay next to the skin, really close to it, which ensures keeping your legs warm, as well as giving you a larger stretch possibility. You can be certain that whichever sport you decide to practice whilst wearing them, it will be ok as they will adapt to your movements.

On top of that, the breathability is really good, so you don’t have to be concerned about feeling trapped or too hot inside of them. Also, they can be worn as underpants on really cold days, no need to wear them or use them only for sports activities.

Finally, they are machine washable and very durable. Reviewers said they have had them for years and washed them numerous times and they still work perfectly.


  • Really comfortable, soft and lightweight
  • Very warm
  • Not itchy


  • Some reviewers found them a bit too big, baggy

Related: The Darn Tough Athletic Socks are a good add-on to get with the under pants, as they will keep your fit warm and comfortable during winter sport activities.

Check the price on Amazon

Smartwool 0SS603 Smartwool 0SS603

Price: $90 – $120

Dimensions: 12 x 11 x 2 inches

Weight: 340 grams

Specific features: This base layer features all Merino wool, with interlocking weaves, and zipper, shoulder panels, and flat seams.

Best use: Skiing

Description: The Smartwool 0SS603 Zip T is one of the best base layers on the market because it is soft and wicks away moisture effectively and it repels odors, too! This is a warm base layer that is great for skiing, biking, running and hiking, plus it has a UPF 50+ protection level.

This base layer was specifically designed for skiing or for high performance winter activities. It is one of the warmest layers out there, so if your idea is to buy it for autumn runs, you’re probably better with another lighter model.

However, this base layer will not disappoint. It will keep you warm, it will fit your upper body very well, and it stretches and moves very well. It allows you to do any kind of movement very comfortably.

The only issues with this product are the cost it has, but it is perfect when it comes to comfort and performance!


  • One of the warmest models
  • Specifically designed for skiing or high performance winter activities
  • Very good fit


  • Slightly expensive

Related: Being a skiing base layer, the Smartwool Merino 250 Baclava is the perfect match. It will protect your face, head and neck from wind, snow and cold while skiing.

Check the price on Amazon

Wrapping It Up

That’s the end of the list! You now know what types of base layers are out there as well as the materials that are used. You also know what type of weight to choose in the weather that you are going to be out in and have learned what the important factors are when choosing a base layer like warmth, durability, and comfort.

A highly breathable base layer like the tasc model is enough to make our reviewers dance

Product reviews showed you some of the great products on the market that may work for you. Now you get to go out and make a great choice and enjoy any type of weather while exercising.

What other base layers belong on this list? Are there any specific features we missed out that you might think of? Let us know in the comments below!


Kane Dane


  • Great article. I’m going to buy the smartwool. It seems like a great base layer that I could keep in my closet for the right time. What base layer do you prefer?

  • I am still confused in what to buy. Do you have any idea about what sort of a base layer will be suitable for a little fat person?


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