How To Combine Base Layers & Hiking Clothes

How you combine base layers and all types of hiking clothing (jackets, pants, etc) for hiking? In this post you will learn how to combine all depending on weather conditions. That is one of the top and most important lessons a hiker needs to know, next to safety.

What are Base Layers?

You may have heard them as thermal clothing too. A base layer is what you wear when weather gets cold, directly on your skin. Most think that when weather is such, they need to wear plenty and thick clothes. That is not correct. A key ingredient in winter hiking is the “onion layers” clothing.

Base layers (thermal clothing) are made for such reason. They have plenty of properties depending on their materials and their results change depending on how well you combine them with all other hiking clothing, as you hike!

Apart from that, base layers can be as well used in city walking when weather is cold. They are not exclusively for hiking or/and mountaineering.

What are Base Layers made from?

Nowadays, as materials evolved, base layers are worn for non-hiking reasons too. The reason why is they are elastic, light and flexible to be a “winter t-shirt”, that keeps you warm and allows you not to wear multiple heavy clothes to get warm.

The most popular materials they are made with are: Polyester, Poly-amid, Polypropylene, Wool, Merino Wool. They slightly differ per season.

On top of the materials, the actual weaving of the materials plays an important role to the efficiency, quality and seasoning of the base layer. To cut it short: Thick weaving is met to winter base layers and thus keeps the body temperature as steady as possible.

Thick weaving doesn’t mean that the base layer will end up being thick. On the contrary, it will be light and thing.

In that way, you can choose the proper per activity material. For skiing or mountaineering you must choose a breathable material, as the last thing you would like is to swim in your own sweat. 

Base layers made from wool, will keep body temperature in a normal level, even after they get wet.

Under the same logic, there are base layers that are not suitable for days with radical changes of temperature, i.e. from very cold to hot. Such conditions may happen when you walk through a forest in winter and then rise up to bright sun without wind cooling you down.

There are some exceptions with base layers that perform really well both in high and low temperatures. 

Here is a break down of different materials for base layers and their benefits.


That is the most common type for long underwear. Why?

  • Super fast to dry
  • Durable
  • Inhibit odor retention (for multi-days trips bring more or have some tolerance)

Merino Wool

Not the itchy type of wool. It is soft with fine fibers. As a material it is used as a supplementary material with other fabrics (i.s. spandex). Why it is great? 

  • It wicks well (some moisture is retained in wool and gets a bit longer to dry) 
  • Is cooler (gets cooler when weather is warmer)
  • Durable, but up to some point (if you carry a heavy backpack it will wear through with time) 
  • Odor free (Wool is highly resistant to bacteria causing odors) 


Extremely soft but not for tough conditions. Why?

  • Not so good wicking (when lots of sweating is involved)
  • Lightweight but not durable 
  • Keeps odors in 


This “technology” involves wool embedded with ceramic particles. Such clothing is for hot weather only, as ceramic will attract body heat and at the same time will dissipate it quickly, thus leaving you far more cooler. 

How to choose Base Layers?

In summary, there are 3 main factors to take into consideration.

Materials: Either synthetic or wool, it needs to keep the sweat off your skin. This is called “wicking”. 

Weight: You will meet 3 types of “weights”. These are: Lightweight, Mid-weight, Heavyweight. The thicker, the warmer it gets. 

Fitting: Fabric has to be in direct contact with your skin to be efficient. You don’t want to feel it “tight” buy more like a snug fit.

How to wear Base Layers with hiking clothes?

One of the most discussed topics between amateur hikers is how to combine clothing under different weather conditions. Before moving to the analytic diagram for this, lets state what “different weather conditions” really means.

Hiking can happen in many different types of terrains, under different (and changing) weather conditions.

For example, it can be sunny and cold, but then it can get colder as you walk through a forest, then it can become even colder as you get out of the forest to a hill side where North cold wind blows, etc, or it can become warmer.

When you walk you can meet all kinds of conditions. What do you wear when things are like that? There you need the “onion layers” clothing.

Here is the table explaining how to do that. With mid-layer we mean either a fleece or loft jacket. With outer layer we mean a hardshell or shoftshell jacket.



Base Layer

Mid Layer

Outer Layer

base layerbase layerbase layer
High temperatureDry weatherKeeps you dry from sweat
base layerbase layerbase layerbase layer
High temperatureMoisture, rain, windyKeeps you dry from sweatProtects from rain & wind
base layerbase layerbase layerbase layer
Low temperatureDry weatherKeeps you dry from sweatKeeps you warm
base layerbase layerbase layerbase layerbase layer
Low temperatureMoisture, rain, windyKeeps you dry from sweatKeeps you warmProtects from rain & wind
base layerbase layerbase layerbase layerbase layer
Very low temperatureDry weatherKeeps you dry from sweatKeeps you warmProtects from rain & wind
base layerbase layerbase layerbase layerbase layer
Very low temperatureMoisture, rain, windyKeeps you dry from sweatKeeps you warmProtects from rain & wind

How Base Layers actually “work”? 

Here is the brief explanation.

There is a thin polyester layer in the inner part of base layers. That acts as an insulation layer. That layer absorbs the moisture from the body and “pushes” it out. In that way your skin remains dry.

The question here is: why to keep the skin dry?

The “elders” said that when you get sweaty and the surrounding temperature is low then you will feel that external cold multiplied and on your skin. That invites the risk of getting a cold, plus your energy will gradually decrease as your body will try to balance internal with external temperature. 

As this happens you will also need to consume more energy (food), but that won’t equalize the effect of freezing further. On top of that, the extra sweat is really annoying by itself, right?

Base layers, due to their thicker weaving, keep the temperature where it is meant to be and doesn’t allow it to “get out”. So, you keep yourself warm, by using your own production of heat. Moisture is expelled from your skin, which also leaves you with less odor and lack of microbes that love moisture.

Base layers are meant to wear directly on your skin, without any other fabric between your skin and them. Regarding the size, it must fit but not being too tight. It needs to be elastic enough so you can have all ranges of motion. 

What types of Base Layers are out there? 

There tshirts, tops, bottoms, socks and gloves. Choose as many as needed depending on the conditions. The good thing is that they are light and really compact so they take very little space and weight in your backpack.

Thermal (Base Layer) Tops

Even if you don’t hike through really cold terrains, you can replace some of your cotton long sleeve shirts with base layer ones. 

There are many options. From base layers that look like a typical shirt, to very technical ones suitable for extreme temperature conditions and turnarounds. 

The ones that “resemble” a typical t-shirt are the ones you can wear in the city too.

Smartwool Merino 250 Base Layer Crew Top

How To Combine Base Layers & Hiking Clothes
Fabric: 100%, merino wool
Moisture Wicking: Yes
Quick Drying: Yes
Underwear Weight: Midweight

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In Amazon In REI


Patagonia Capilene Midweight Zip-Neck Top

Fabric: Recycled polyester/polyester
Moisture Wicking: Yes
Quick Drying: Yes
Underwear Weight: Midweight

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Men’s Women’s


WoolX Glacier Base Layer Crew 

How To Combine Base Layers & Hiking Clothes
Fabric: 100%, merino wool
Moisture Wicking: Yes
Quick Drying: Yes
Underwear Weight: Heavyweight

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Men’s Women’s


Icebreaker Merino Oasis Crew Neck Shirt

Fabric: 100%, merino wool
Moisture Wicking: Yes
Quick Drying: Yes
Underwear Weight: Lightweight

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Men’s Women’s

Base Layer Tights or Thermal Pants

These are suitable for very cold weather hiking, but will be also useful when you stroll in the streets of a really cold (North) European city, where temperatures drop really low. We found a pair of base layer bottoms to be a lifesaver in our trip to Moscow during New Years Eve. Temperatures dropped to -20oC and winter pants were not enough.

There are women specific tights you can use as they are (without extra pants) for either hiking or running and there are bottoms you can use as underpants. See this post about women specific hiking leggings.

Men have their own base layer underwear too (short or long). Apart from keeping your “privates” warm, they are really elastic. During many hours of hiking you don’t definitely want sweaty cotton underpants.

In case your work involved spending too much time outside they are perfect for that too.

Hot Chillys Women’s Micro-Elite Chamois Tight

How To Combine Base Layers & Hiking Clothes

Fabric: 89% polyester/ 11% lycra spandex
Moisture Wicking: Yes
Quick Drying: Yes
Underwear Weight: Midweight

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In Amazon 


Outdoor Research Men’s Alpine Onset Bottoms

How To Combine Base Layers & Hiking Clothes

Fabric: 100% Merino Wool
Moisture Wicking: Yes
Quick Drying: Yes
Underwear Weight: Midweight

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In Amazon 


Thermal (Base Layer) Socks

In the same logic, thermal socks are great if you want to keep your feet warm. They come in short and long (up to your knee).

Heatgear Tech Crew 3Pk Unisex Socks

How To Combine Base Layers & Hiking Clothes

Fabric: 97% Polyester, 3% Elastane
Moisture Wicking: Yes with Anti-odor technology

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In Amazon 


For special occasions you can always add some extra gear to keep your head warm. Balaclavas are such gear. These cover most of your head and face, thus highly decreasing the loss of body heat. 

Base Layer clothing maintenance

The same rule for all “technical” gear as this one, applies here. Follow the manufacturer’s instructions for washing, cleaning and storage. Such clothes are usually washed in 30oC and not in a laundry machine. 

Do not use softeners or “hard” detergents as such decrease the life cycle of base layer clothing.

Such clothes usually dry very fast, and that is another reason they are preferred from outdoor activities enthusiasts. 

Want to learn more about hiking gear? Explore more posts from our hiking gear section, like: Ultralight Backpacking Gear BasicsBest Trekking Poles for Men and WomenBest Hiking Leggings for WomenBest Hiking Gloves and many more.

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