What are the best base layers for cold weather? You’ve essentially got two choices: merino wool or synthetics. These provide your body with the best resistance against biting winds and harsh temperatures. Without properly insulating your body, you’re putting yourself at risk of hypothermia. The two solutions mentioned above offer the best protection in extremely cold weather, which you’re likely to encounter above a certain elevation and/or in the depths of the winter season. We cover the topic in further detail in the rest of this article, so read on!
The Importance of Retaining Temperature When Mountaineering
Mountaineering is not a walk in the park—far from it. Too many tend to place it on equal footing with hiking, whereas in reality, traversing mountains, especially those that tower high above elevations that most of us have ever tread, involves braving the harshest conditions possible.
If you’re considering setting out on a trip like that, adequate preparation will be key to staying clear of potential danger to your health and safety. Specially designed mountaineering boots are a must, but these mark just the beginning of your winter camping essentials you’ll need to bring along. Maintaining body heat is going to be your number one priority throughout the trip, and to that end, you’ll have to rely on thermal and properly insulating base layers.
Best Base Layers for Extreme Cold
So, what are the best types of base layers of clothing for cold weather? There are a number of options to consider, which we break down below.
Merino Wool
Merino wool is a tried and tested classic. Praised for its excellent breathability and absorption, this fabric rises to the challenge every time, regardless of whether it’s a steep climb up a cliff face or a prolonged trek trudging through ankle-deep snow.
Synthetic Fibers
Synthetic fiber clothing comes in as a close second, right behind merino wool, chiefly for two reasons. First, they boast incredible moisture-wicking properties and dry super quickly. Secondly, the price tag compared to top-of-the-line merino is significantly lower. Granted, synthetic fiber clothing can get pretty smelly as they aren’t as good at sweat absorption, but your mileage may vary.
Bamboo
Ever since its emergence on the market, bamboo has definitely been making a splash. They boast similar characteristics to merino wool with antimicrobial qualities and extra breathability and make for a great choice for those who are either allergic to wool or prefer to buy vegan. The downside is that due to bamboo base layers being relatively new, their prices remain rather high.
Hybrid Blends
Plenty of options are available out there that mix and match between these different options. These represent the best of many worlds, combining different materials to maximize their strengths. Merino-synthetic blends enjoy particular popularity, and even though they may not perform as well as pure merino wool base layers, they’re often more durable as a bonus upside.
Choosing the Right Base Layer for Cold Weather
We’ve laid out the options, but how can you know which is the best base layer for mountain trekking in your specific case? As usual, planning ahead makes such important judgment calls much easier, and in this case, looking at things through the lens of the expected levels of intensity will help you make an informed decision.
Essentially, the harsher the conditions, the thicker and heavier your base layers should be. We break down our recommendations based on this criterion below.
Lightweight
Thinner base layers with a typical basis weight of 150-200g/m² are ideal for high-intensity activities or less extreme conditions. Think fast-paced treks or intense climbing sessions rather than cozying up in the tent, getting ready to sleep through the night. Lightly-woven layers are better at moisture management and prevent overheating during particularly strenuous activities.
Midweight
Midweight fabrics are best suited for situations where you need to strike a balance between warmth and breathability, or simply when you want to be reasonably well prepared for everything. They’re the true all-rounder, all-purpose solution that can provide sufficient warmth even when temperatures drop quite a lot.
Heavyweight
As you might expect, heavier fabrics (250 g/m² and above) come into the fold whenever your body’s the least active and/or when the temperature drops into the barely survivable, frigid, and icy range. These base layers are perfect for the extreme cold as they provide maximum insulation. You probably don’t want to wear them in the midst of high-intensity activities, though.
The Takeaway
Choosing the best base layer for cold weather mountain hiking comes down to understanding both your projected activity levels and the harshness of the conditions you’re going to encounter. Merino wool remains the gold standard for its natural temperature regulation and odor resistance, though synthetic options offer a budget-friendly alternative with excellent moisture-wicking properties.
Above all, a good base layer forms an essential element of your cold weather camping gear assembly. Take the time to choose the right material and weight for your specific needs, and you'll be well-equipped for whatever the mountain throws at you.
You may also read: Merino Wool vs. Synthetic – Which is Better for Mountain Hikes?