A base layer in winter clothing is the layer that is closest to your skin (i.e., underwear). With winter clothing, this layer is crucial because, if it’s made of the wrong material (like cotton), it might trap sweat adjacent to your skin and reduce your body’s ability to retain heat. In severe weather, this might be lethal.
The warmest base layers are constructed of synthetic or natural fibers that wick moisture away while trapping heat close to your body. We are constantly looking for the highest-quality apparel in each category we cover on this website. 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 5 Warmest Women’s Midlayers 2024!“
1. First Lite Women’s Furnace Hoodie Base Layer
The First Lite Women’s Furnace Hoodie Base Layer is a super heavy-duty Merino wool base layer. It is a 95% Merino and 5% Spandex blend. Its weight comes in at 21 ounces (595g). It is constructed with a heavyweight 350 grams per square meter (gsm).
Another thing I like about this base layer is it has a hoodie! That sounds handy to me, especially if you are ever sleeping in a sleeping bag while camping. That could help keep your head warm.
This base layer is extra heavy to keep you warm when hunting, and you must hold still. For example, if you are waiting in a blind or up in a tree stand.
Merino wool and the Spandex blend wick away moisture from your skin. They are also breathable and help regulate your body temperature so you don’t get too warm.
Pros:
- Heavy Merino Wool: This garment weighs a full 21 ounces (595g).
- 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 Women’s Thermal Base Layers
I will include two of their base layer garments as number 3 in this list. The first is the Icebreaker ZoneKnit™ Merino Zip Hoodie, and the second is the Icebreaker 260 Tech Merino Zip. The ZoneKnit™ garment is a fleece fabric of 50% wool and 50% Lyocell, a more natural synthetic derived from trees. The 260 Tech garment is 100% Merino wool.
The ZoneKnit™ is very heavy, weighing 28.34 ounces (720g), and the 260 Tech weighs 9.52 ounces (270g).
The ZoneKnit™ garment has a hoodie that almost turns the hood into a balaclava when you zip it up. It is pretty cool. I think it would be great if you were sleeping in a sleeping bag on a cold winter night. The 260 Tech garment doesn’t have a hoodie but a half zipper and a high collar.
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 Women’s Intraknit™ Thermal Max Merino Base Layer
The Smartwool Women’s Intraknit™ Thermal Max Merino Base Layer is a heavy-duty 100% Merino wool base layer. The top weighs in at 8.89 ounces (252 g). It is constructed with a heavyweight 250 grams per square meter (gsm).
The 1/4 Zip neck zipper is a nice feature that allows you access to extra ventilation should you need it. 3D knitting technology allows Smartwool to add performance features to the garment without seams.
Merino wool is naturally great at wicking moisture away from your skin. It is also very breathable, making the garment a great temperature regulator so you don’t get too hot. Merino wool is also naturally resistant to odors.
Pros:
- Heavier Merino Wool: This garment weighs 8.89 ounces (252g).
- 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
This base layer tee is designed for men, but the company told me they will come out with a women’s version soon. I included it early because the technology is amazing; some of you might want to know about it now.
The Fortress All Weather Gear BasePro Tee tops my list of 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.
The owners of Fortress All Weather Gear tests this insulation often. To do this, they drive up to a frozen lake in -10F (-23C) weather, cut a hole in the ice, and jump in! I’m not kidding; they really do this!
Within a minute or two after getting out of the water, the person who jumped into the frozen water is no longer shivering but is warm and comfortable. They don’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.
By the way, this garment 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 Women’s Capilene® Air Base Layer Hoodie
The Patagonia Women’s Capilene® Air Base Layer Hoodie is made of 51% Merino wool and 49% recycled polyester, a blend designed to wick moisture away from the skin as well as retain warmth close to the body.
As I was reading about the fabric this garment is made out of, they said they use HeiQ®, in it, which helps to regulate your temperature so you don’t get overheated. The fabric naturally controls odor as well.
The garment is designed with what they call “flatlock seams.” This is supposed to minimize chafing. Nobody likes chafing!
It has a long center-front zipper that vents body heat. Its sleeves are designed with elastic thumb loops. This helps secure the sleeves down to your hands.
Pros:
- Warm: This garment is made from one of the warmest natural and synthetic blend fabrics.
- Hoodie: A hoodie on your base layer is a benefit when sleeping in a bag.
- Wicks Moisture: Wool and polyester blend fabric is highly moisture-wicking.
- Breathable: Wool and polyester blend 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
You should always wear a base layer when it’s cold outside. This lightweight, insulating layer of clothing, usually worn next to the skin, is essential for retaining body heat and wicking moisture away to keep the wearer comfortable and dry. A base layer is a necessary barrier against the biting cold by successfully regulating body temperature and avoiding perspiration buildup, enabling people to participate in outdoor activities and sustain prolonged exposure to wintry elements without discomfort or frostbite.
Thank you for reading this article to the end. If you have learned something or benefited from this article in any way, please remember to share it on your social media. That helps us grow our reach and get the word out! Thank you!