Updated on May 25, 2022

As the temperature begins to drop, some people opt to retreat indoors to the comfort of a climate controlled environment. For those that dare to brave the cold and wind that often accompany activities like skiing and snowboarding, snowshoeing, and winter hiking and climbing, layering is essential. Selecting the right base layer can be as important as choosing the right sock for those brand new boots. A base layer will be the first line of defense that your body will have in regulating your core temperature and helping to transfer moisture away from the body during active pursuits. With so many manufacturers and fabric options to choose from, the task of selecting the best base layer can feel like an overwhelming endeavor.

Don’t sweat it! Here at The Adventure Junkies, we pride ourselves in helping you choose the best gear for your upcoming cooler weather adventure. In this guide, we’ll help you pick the best base layer so you can stay warm and insulated on your next foray into the great outdoors.

For more of our top hiking apparel recommendations, check out these popular articles:

Base Layers for Women | Wool Base Layers


Quick Answer - The Best Base Layers for Hiking

  1. SmartWool Merino 250
  2. Patagonia Capilene Midweight
  3. MeriWool Midweight
  4. Smartwool Merino 150 Crew Top
  5. Patagonia Capilene Bottoms
  6. REI Midweight Bottoms
  7. Smartwool Merino 150 Bottoms
  8. REI Lightweights
  9. Smartwool Merino 250 Bottoms


Comparison Table - Best Base Layers for Cold Weather Hiking

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SmartWool Merino 250Long Sleeve Crew TopMidweightMerino wool$$4.9Read Review
Patagonia Capilene MidweightLong Sleeve Crew TopMidweightRecycled polyester$4.8Read Review
MeriWool MidweightLong Sleeve Crew TopMidweightMerino Wool$4.4Read Review
Smartwool Merino 150 Crew TopLong Sleeve Crew TopLightweight87% Merino Wool/13% Nylon$$4.8Read Review
Patagonia Capilene BottomsBottoms With Fly OpeningMidweightPolyester$4.8Read Review
REI Midweight BottomsBottoms With Fly OpeningMidweightPolyester$4.6Read Review
Smartwool Merino 150 BottomsBottoms With Fly OpeningLightweight87% Merino Wool / 13% Nylon$$4.8Read Review
REI LightweightsBottoms With Fly OpeningLightweight92% polyester/8% spandex$4.5Read Review
Smartwool Merino 250 BottomsBottoms With Fly OpeningMidweightMerino wool$$$4.5Read Review
Want to learn more about a technical term? Check out our Features Explained section below.

Need buying advice? Take a look at these Things to Consider.

Reviews - Best Cold Weather Hiking Base Layers

SmartWool Merino 250

  • Material: Merino wool
  • Insulation: Midweight
  • Style: Long Sleeve Crew Top
  • Moisture Wicking: Yes
  • Fit updated with shoulder panels to eliminate shoulder seams for improved functionality
  • Flatlock seam construction minimizes rubbing and chafing
  • Ribbed elbows enhance flex and durability


If you’re looking for a base layer that performs well in every category, consider the Merino 250. Made from 100% Merino wool, this base layer excels at regulating temperature, wicking moisture, and providing for microbial resistance. It’s definitely an all-in-one package. For such lightweight material, this base layer is impressively warm.

What we like most about the SmartWool Merino 250 is due to the ultra thin nature of the fibers, they flex against the skin, making for a super soft, comfy fit.

Patagonia Capilene Midweight

  • Material: Recycled polyester
  • Insulation: Midweight
  • Style: Long Sleeve Crew Top
  • Moisture Wicking: Yes
  • Hollow-core yarn construction increases wicking performance and speeds dry times
  • HeiQ Fresh durable odor control
  • Droptail hem extends coverage


This synthetic alternative serves as a high-quality all-around base layer than costs half as much as Merino wool alternatives. The top is constructed from 100% recycled polyester material — making for an appreciated eco-friendly option. The layer provides for top-notch warmth and moisture-wicking capacities. Patagonia applies an anti-odor treatment to this top, as well, allowing you more wear time in between washes.

What we like most about this base layer top is how affordable it is compared to Merino alternatives in conjunction with its comparable quality.

MeriWool Midweight

  • Material: Merino Wool
  • Insulation: Midweight
  • Style: Long Sleeve Crew Top
  • Moisture Wicking: Yes
  • Acts as a base layer or mid-layer
  • Natural odor-resistant properties
  • Lightweight


If you are looking for an affordable base layer that offers the same performance as Merino Wool options without the hefty price tag, you’ve likely met your match. The company integrated ultra fine Merino wool fibers into its construction. Despite being made of wool, this mid weight top is surprisingly breathable, too, making for a great choice for high intensity activities. It’s important to note this extra breathability does reduce the warmth of the top, making it an ideal choice for wearing in spring and fall.

What we like most about this base layer is that its made from 100% Merino Wool yet costs only $60.

Smartwool Merino 150 Crew Top

  • Material: 87% Merino Wool/13% Nylon
  • Insulation: Lightweight
  • Style: Long Sleeve Crew Top
  • Moisture Wicking: Yes
  • Raglan Sleeves (No Shoulder Seam And Extra Space For Movement In The Underarms)
  • Flatlock Seam Minimizes Chafing
  • Nylon Increases Durability Of The Merino Wool


Paired with the bottoms by the same name, the pair will blanket you in extreme comfort and protection from neck to ankle. And just like bottoms, the top is created by spinning the merino wool around a nylon core to create a durable and lightweight layer that places the soft wool next to your skin where it prevails at keeping you insulated while wicking moisture away from the body. The raglan sleeves ensure that there’s no seam along the shoulder and that extra room exists in the underarms for freedom of movement. The lack of a seam along the shoulder is ideal when wearing a pack, so you won’t have uncomfortable stitching digging into your neck and shoulders while you hike.

Patagonia Capilene Bottoms

  • Material: Polyester
  • Insulation: Midweight
  • Style: Bottoms With Fly Opening
  • Moisture Wicking: Yes
  • HeiQ® Fresh antimicrobial treatment
  • Soft, brushed, fast-drying elastic waistband
  • Flatlock seams minimize chafing
  • Fair trade certification


Patagonia’s synthetic Capilene series is changing how we envision synthetic base layers — if you’re looking for an alternative to wool that keeps you just as warm and performs just as well, look no further. Patagonia crafted these bottoms from 100% recycled polyester in a diamond grid knit pattern that provides for superior warmth for its weight. These base layers also give wool a run for its money in terms of comfort thanks to the fleece-like interior feel. These are also coated with Patagonia’s proprietary odor control treatment to keep you feeling fresher longer.

What we like about the Patagonia Capilenes is how affordable they are for a synthetic product that rivals premium wool alternatives currently on the market.

REI Midweight Bottoms

  • Material: Polyester
  • Insulation: Midweight
  • Style: Bottoms With Fly Opening
  • Moisture Wicking: Yes
  • 4-way stretch delivers a flexible range of motion
  • Flatseam construction
  • Soft elastic waistband


This synthetic alternative serves as a high-quality all-around base layer that costs half as much as Merino wool alternatives. REI uses sustainable polyester and labels these as Fair Trade certified, which should leave you feeling good about minimizing your impact on the planet. The 4 way stretch and a flat seam construction ensure for a full range of motion when you’re on the go.

What we like most about REI’s base layer bottoms is the built-in sun protection, providing for a UPF rating of 50.

Smartwool Merino 150 Bottoms

  • Material: 87% Merino Wool / 13% Nylon
  • Insulation: Lightweight
  • Style: Bottoms With Fly Opening
  • Moisture Wicking: Yes
  • Smooth Seams Minimize Chafing
  • Slim Fit
  • Fully Functional Fly


For over twenty-five years, Smartwool has been creating high quality products utilizing merino wool. The American based company was founded in Steamboat Springs, Colorado and was acquired by the VF Corporation (the same parent company that owns The North Face as well as other notable brands) in 2011. 

This lightweight, merino wool bottom layer is ideal for active pursuits in which breathability and the regulation of body temperature are paramount to the activities ahead. The wool’s natural properties help it to resist odors even when worn day after day. The wool is combined with nylon to create a more durable product while maintaining all of the superb properties of merino wool.

REI Lightweights

  • Material: 92% polyester/8% spandex
  • Insulation: Lightweight
  • Style: Bottoms With Fly Opening
  • Moisture Wicking: Yes
  • UPF 50+ sun protection
  • Ankle-length inseam
  • Flatseam construction and low-profile waistband


If you’re looking for a base layer that’s more affordable than wool but performs well during high-intensity activities, these are a great option to consider. These polyester blended bottoms are perfect for sleeping in the backcountry and staving off the early morning chills before hitting the trail again. They provide for a level of odor resistance and are very quick-drying. When combined with their affordability, this makes them ideal for backcountry adventures in mild weather conditions.

What we like most about these bottoms is how well the semi-fitted design layers with other pieces of clothing.

Smartwool Merino 250 Bottoms

  • Material: Merino wool
  • Insulation: Midweight
  • Style: Bottoms With Fly Opening
  • Moisture Wicking: Yes
  • Merino wool–covered elasticized waistband
  • Interlock-knit merino wool enhances comfort, breathability, thermoregulation and odor-resistance


If you’re looking for a great balance of comfort, warmth, and performance, give these a look. These are Smartwool’s warmest base layer bottom offering thanks to a combination of thick-cut wool and an interlocking knit design. The waistband features flat lock seams and wool in just the right places to provide for extra comfort and reduce the potential for chafing. Despite how warm these base layer bottoms are, their breathability and moisture wicking capabilities are on par with similar alternatives.

What we like most about these bottoms is how the redesigned gusset in the crotch improves the fit and flexibility.





There are a multitude of options to choose from in the baselayer market. For this particular guide, we’re only going to concentrate on the top three: Merino Wool, Synthetic, and Hybrid (blend of merino and synthetic). Choosing the best base layer can be a matter of preference as well as preferred choice of material.

Merino Wool

This is not the itchy wool your parents and grandparents wore. Merino wool is the only natural fiber in this guide and its natural properties make it ideal for warmth, odor control, and wicking properties. The fibers are thinner and softer than traditional wool. Wool tends to keep you warm even when it gets wet and naturally repels odors so you don’t have to worry about stinking up a wool base layer even if you wear it for weeks on-end during a thru-hike or multi-day ski trip.


Until Merino came on the scene, synthetic base layers ruled the roost. Polyester is still preferred by many and with exception to odor control, it excels in the areas of durability, warmth and breathability.


Hybrid base layers possess the best of both worlds. Blended products incorporate the best properties of Merino wool and polyester. However, this option can also be one of the more expensive options.



There are 3 main categories of insulation: lightweight, midweight, and heavyweight. Some manufacturers may label the insulation levels differently, but they typically fall into one of those categories.


This is the thinnest and perhaps the most ideal for active pursuits on moderately cold days. Lightweight layers made from Merino wool can be less durable than polyester products as the thinner wool products tend to wear faster and may only last a few seasons while their synthetic counterparts can last substantially longer.


As the name implies, this insulation weight is middle of the road. It’s a perfect base layer for active endeavors on cold days. It can also be worn as a standalone layer on cooler days.


This is the paramount choice for relatively sedentary activities. The extra thick base layer can be overkill for activities like cross-country skiing, hiking, and even downhill skiing except on perhaps the coldest days.



To perform optimally, base layers should fit relatively snugly and perform like a second skin. The closer the material is to your skin, the better it can perform its intended purposes of moving moisture away from your body. Though, at the end of the day, it’s important to choose a product based on your particular needs and preferences for fit.



Premium products often carry a premium price. While relatively moderately priced, base layers can be as essential as mid and outer layers. This will be the first layer of defense against the elements and it will be next to your skin. Therefore, it’s important to choose a layer based on its properties, fit, and comfort. Saving money won’t pay dividends if you end up shivering and cold sitting on a chair lift.



Layering is the key to thriving in active pursuits during cooler weather. Choosing a quality base layer is as essential to your overall comfort as building a proper foundation before building a house. This sets the stage for the performance of all subsequent layers.





Consumers seeking textile products that meet stringent environmental standards can rest assured when finding the “bluesign” designation label on a product. To receive this designation, a product must conform to these standards from the beginning to the end of the production process. Patagonia was the first brand member of Bluesign Technologies.


Wicking is a fabric’s ability to draw moisture away from the body. Unlike cotton which absorbs moisture and makes it less than ideal for an insulating layer, natural fibers like Merino wool and synthetic fabrics like polyester are excellent moisture-wicking fabrics.


Tops with a crew neck have a round neckline with no collar.


As the name implies, tops featuring a half-zip (sometimes only feature a quarter-zip) allows the user the option to unzip to allow for further ventilation and it makes removing over a helmet or other gear easier than a crew neck. Also, the higher neckline provides more warmth as the neck can often be an exposed area.


A raglan sleeve consists of one continuous piece of fabric that extends from the collar to the underarm. There is no shoulder seam in this style of shirt or jacket, which makes it more comfortable while wearing a pack because you won’t have uncomfortable seams digging into your shoulders while you hike.


Seams are butted together and joined with stitching to provide a nearly seamless design to avoid overlapping of layers.


When the back of the shirt or top is longer in the back than the front. This assists in helping to keep the shirt tucked in during active pursuits when regular hemmed products might come untucked.


In apparel design, a gusset is typically a triangular piece of fabric (can also be other shapes as well) that when sewn into a seam can increase mobility. These are often added to regions like the underarm, crotch, and other areas that might benefit from extra area in the product.