In winter clothing, a base layer is the layer next to your skin. Your underwear, in other words. This is a particularly important layer because if made from the wrong fabric (cotton, for example), it can hold moisture from your sweat next to your skin and drain the warmth from your body. This could be fatal in extreme conditions.
So, the warmest base layers are made from natural or synthetic fibers that wick the moisture away and hold the warmth close to your body. On this website, we are always interested in finding the highest quality clothing in each category we discuss. And in this article, we are also wanting the warmest.
So, I have compiled a list of what I believe are the top five highest quality warmest base layers on the market in 2024. So, let’s get into it! See my related article: “Top 10 Warmest Men’s Midlayers 2024!“
1. First Lite Men’s Furnace Base Layer Hoodie
The First Lite Men’s Furnace Base Layer is a heavy-duty Merino wool base layer. It is a 95% Merino and 5% Spandex blend. Its weight comes in at 25.5 ounces (722.91g). Not only is it heavy and warm, but it is breathable. It is a very comfortable base layer.
Another unique thing about this base layer is that it has a hoodie. Underwear with a hoodie! What will they think of next? That could be helpful, especially when winter camping.
This hoodie was designed for late-season hunting when it is very cold and you sit still in a blind or a tree stand. I imagine there will be many days where this is the only layer you need to wear, it is that warm.
The hood is designed with two “quiet snaps” that create a comfortable Monk’s style hood collar that helps seal in heat and keep the wind off your neck.
Pros:
- Heavy Merino Wool: This garment weighs a full 25.5 ounces (722.91g).
- Hoodie: A hoodie on your base layer is a benefit when sleeping in a bag.
- Wicks Moisture: Merino wool is naturally moisture-wicking.
- Breathable: Merino Wool is naturally breathable, holding in warmth while keeping you from overheating.
Cons:
- Price: Because this is a high-quality garment, its cost is higher than lesser quality.
2. IceBreaker Men’s ZoneKnit™ Merino Explore Hoodie
The IceBreaker Men’s ZoneKnit™ Merino Explore Hoodie is a heavy-duty fleece base layer of 50% Merino wool and 50% Lyocell. Lyocell is a more natural synthetic derived from trees. It is a good insulator and provides warmth, not as warm as wool, but it is warm and helps regulate the temperature. It weighs a whopping 28.34 ounces (800g).
The wool and Lyocell this base layer is made of is spun into a fleece-type fabric. Overall, this is a very warm and comfortable base layer. It does a great job and wicking moisture away from the skin.
This base layer also has a hoodie. As I said above, “Another unique thing about this base layer is its hoodie. Underwear with a hoodie! What will they think of next? That could be helpful, especially when winter camping.”
Pros:
- Regulated Warmth: Merino wool and Lyocell provide warm insulation and help regulate your temperature.
- Hoodie: A hoodie on your base layer is a benefit when sleeping in a bag.
- Wicks Moisture: Merino wool and Lyocell are naturally moisture-wicking.
- Breathable: Merino Wool is naturally breathable, holding in warmth while keeping you from overheating.
Cons:
- Price: Because this is a high-quality garment, its cost is higher than lesser quality.
3. Smartwool Men’s Intraknit™ Thermal Max Merino Base Layer
The Smartwool Men’s Intraknit™ Thermal Max Merino Base Layer is an extra-warm, comfortable, high-quality base layer. It is made out of 100% Merino wool. The garment weighs 298 g = 10.51 oz. Smartwool is based in Colorado but has these knitted in India.
The idea behind the 1/4 zip is it allows for increased ventilation should your activity level increase and you need it. The shoulder panels make it more comfortable with a pack.
Another nice thing about Smartwool is they have more base layer tops to choose from, different weights, and different colors.
The only thing to worry about with a Merino wool base layer is wool needs to be cared for properly to keep it from losing shape or sagging over time.
Pros:
- Heavier Merino Wool: This garment weighs 10.51 ounces (298g).
- Wicks Moisture: Merino wool is naturally moisture-wicking.
- Breathable: Merino Wool is naturally breathable, holding in warmth while keeping you from overheating.
- Chest Zipper: The chest zipper allows extra ventilation when needed.
Cons:
- Price: Because this is a high-quality garment, its cost is higher than lesser quality.
4. Fortress All Weather Gear BasePro Tee
I put the Fortress All Weather Gear BasePro Tee as the first of the synthetic base layers, even though it has short sleeves because it contains Fortress’s patented technologically advanced AERIS™ 250 insulation that keeps you warm even if you get wet.
To test this insulation, the guys at Fortress drove up to a frozen lake in -10F (-23C) weather, cut a hole in the ice, and jumped in! I am not messing with you, they really did this!
They learned that within a minute or two after getting out of the water, the person was no longer shivering and was warm and comfortable. They didn’t even have to change out of their wet clothes.
Below is a video showing one of the tests they made jumping through a hole in the ice. It is pretty cool, I highly recommend taking a few minutes to watch the below video.
This tee is 88% polyester and 12% brushed Spandex with a 4-way stretch. It is rated comfortable if worn without any other layers, down to 10 F (-12C).
Pros:
- Warm: This tee is rated comfortable without any other layers, down to 10 F (-12C).
- Even If Wet: Fortress’s AERIS™ 250 insulation keeps you warm even if soaking wet (see above video).
- Wicks Moisture: Fortress’s AERIS™ 250 insulation is highly moisture-wicking.
- Breathable: Fortress’s AERIS™ 250 insulation is highly breathable, holding in warmth while keeping you from overheating.
Cons:
- Price: Because this is a high-quality garment, its cost is higher than lesser quality.
5. Patagonia Men’s Capilene® Thermal Weight Base Layer
The Patagonia Men’s Capilene® Thermal Weight Base Layer is made using Polartec® Power Grid® fabric, a synthetic polyester blend designed to wick moisture away from the skin and retain warmth close to the body.
It is made with HeiQ®, which helps to cool your body when you get overheated and acts as a “pure odor-control” as well.
It is designed with flatlock seams to minimize chafing. Its long center-front zipper vents body heat and is backed by kissing welts for low-bulk comfort next to the skin.
The sleeves are made with elastic thumb loops to help secure the sleeves down to your hands.
Pros:
- Warm: This garment is made from one of the warmest synthetic insulating fabrics.
- Chest Zipper: The chest zipper allows extra ventilation when needed.
- Wicks Moisture: Polartec® Power Grid® fabric is highly moisture-wicking.
- Breathable: Polartec® Power Grid® fabric is highly breathable, holding in warmth while keeping you from overheating.
Cons:
- Price: Because this is a high-quality garment, its cost is higher than lesser quality.
Final Thoughts
Remember, a base layer is important during the cold winter. This thin but insulating layer of clothing, typically worn closest to the skin, plays a pivotal role in trapping body heat and wicking away moisture, ensuring the wearer remains snug and dry. By effectively regulating body temperature and preventing sweat buildup, a base layer acts as a vital barrier against the biting cold, allowing individuals to enjoy outdoor activities and endure prolonged exposure to wintry elements without succumbing to discomfort or frostbite.
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