Running shoes might get the most attention, but they’re not the only important piece of running gear you’ll need.
A base layer is a long or short-sleeved shirt you’ll wear to help keep you comfy and warm when running in cold weather. Perhaps most importantly, base layers should wick sweat away from your skin, keeping you dry. You can wear a base layer on its own, or add a warm jacket over it.
The best base layers keep you warm and dry, but not hot or uncomfortable. They’ll draw body heat away from your torso while also protecting you from cold and wet weather. Sorting through the various features of base layers can seem confusing, but we’re here to help.
Your complete guide to the best base layers starts right now…
Top 3 Best and Favorites
Smartwool Merino 250 Crew
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Under Armour ColdGear Armour Compression Mock
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New Balance Q Speed Fuel Jacquard Long Sleeve
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1. Smartwool Merino 250 Crew
This baselayer will keep you comfortably toasty when running in cold weather. It’s made from 100% Merino wool with flatlock seam construction to prevent chafing.
Interlock knitting allows for a form fit. You can wear the Merino 250 Crew as a single layer when running in mild temps, or use it as an underlayer when you need to beat winter’s harshest chills.
Instead of shoulder seams, the shirt uses shoulder panels. When you wear a backpack, there are no seams to press into your shoulders.
Keeping the garment clean is easy. Simply machine wash on warm on the gentle cycle and then tumble dry on low.
- Lightweight but warm
- Made from soft 100% Marino wool
- Shoulder panels instead of seams
- Machine washable for easy cleaning
- Minor knubs may appear after several months
Best Dry Active Core
2. Sugoi Thermal Long Sleeve Base Layer
Thermal running gear needs to strike a fine balance: it needs to be warm enough to protect you from the elements, but it can’t be so warm you overheat and sweat excessively.
Fortunately, this long-sleeved thermal should keep you warm but not hot. The soft, notched interior doesn’t just insulate against the cold; it also pulls internally-generated heat away from your body.
This long-sleeve shirt is made from 90% polyester and 10% spandex fleece, making it both lightweight and durable. It’s a semi-fitted shirt designed to hug your body. The shirt only comes in black, but that’s ok. It’s a baselayer, no one will really see it.
Plus, the unique Dri Active Core fabric is light and quick-drying. Sweat is wicked away from the body, keeping you dry. At the same time, moisture from wet weather is prevented from soaking through the garment to make contact with your skin.
There are very few seam lines compared to other baselayers, making this shirt more comfortable and less likely to chaffe.
- Wicks away sweat
- Minimal seams for comfort
- Prevents overheating while still keeping your warm
- Can feel tight
Best 1/2 Zip
3. Icebreaker Merino 175 Everyday Long Sleeve 1/2 Zip
You don’t have to choose between substance and style with the Icebreaker 175 Everyday 1/2 Zip. This long-sleeved running shirt keeps you dry and warm. Merino wool is soft and isn’t scratchy – and unlike polyester shirts – stays odor-free.
This shirt is tough yet won’t weigh you down. It is water-resistant and breathable. You’ll be insulated from rain and snow, but heat and sweat are still pulled away from your body. The thinner merino wool layer keeps you warm without overheating.
The shirt has a short zipper at the top which drops down to about mid-chest. Zip it up to protect your neck from the winter chill or leave it unzipped to reduce any build-up of body heat.
- Half-zip allows for easy temperature adjustment
- Lightweight fabric keeps you warm without overheating
- 100% merino wool construction
- Sizing runs small
Top Lightweight Base Layer
4. Craft Fuseknit Comfort Long Sleeve
This lightweight, long-sleeved shirt is soft and stretchy. Body-mapped fabric structures allow for efficient thermal regulation. You’ll stay comfortably warm–not hot and sweaty.
The unique Fuseknit technology uses seamless knit to prevent chafing and irritation, especially when wearing other clothing on top. It’s made from 67% polyester, 31% polyamide and 2% elastane. The semi-relaxed fit conforms to your body shape while remaining loose enough to allow productive airflow.
The garment is also quick to dry. Moisture is wicked away, instead of allowed to saturate the material. You can run in pouring rain without the shirt becoming soaked and freezing. It’s suitable for mild, cool and cold temperatures.
- Seamless Fuseknit construction
- Stretchable for a perfect fit
- Lightweight and breathable
- Quick-drying and moisture resistant
- No zippers
Best Nike Baselayer
5. Nike Pro Warm Long Sleeve
Looking for a base layer that fits as comfortably as your favorite T-shirt? Try this Nike long-sleeve. It’s made from a soft DriFIT fabric consisting of 88% polyester and 12% spandex.
The top is lightweight and breathable. Sweat and moisture are pulled away from your skin. Additionally, a flat-seam design helps prevent abrasions and irritations against your skin.
The semi-fit style is great if comfort is your main consideration. However, the shirt still fits snugly enough that you can easily layer other garments on top.
This top is also made with 75% recycled fabric, so it’s environmentally friendly – and will keep you warm.
The women’s version comes with a 1/4 zip for helping to regulate your body temperature as you run.
- Comfortable polyester/spandex blend
- Wicks away sweat and moisture
- Flat-seam design prevents skin irritation
- Made with recycled materials
- Not as warm as other base layers
Top for Cold Weather Running
6. Under Armour Base 4.0 Crew
It’s like wearing a flexible suit of armor that protects you from the cold! The 4.0 Crew base layer from Under Armour has a brushed negative grid interior that traps hot air, keeping you warm even in the coldest conditions. It’s made from 92% polyester and 8% elastane.
The next-to-skin fit hugs your body tightly but remains comfortable. Four-way stretch construction allows you to move in any direction without hindrance.
It’s fast-drying even in wet conditions. Under Armour’s microthread material wicks away sweat and body heat while a mesh panel in the back of the shirt provides increased ventilation.
- Grid interior creates a toasty layer of warm air
- Next-to-skin fit allows for easy layering
- Four-way stretch construction for easy movement
- Made with high-quality materials
- Water resistant and fast drying
- Next-to-skin fit can feel tight
Most Breathable Baselayer
7. Salomon Explore/Comet Seamless Half Zip
This breathable base layer has the features you want when running. And it works easily as well for a base layer on cold days or an outer layer during cool and mild weather.
Active Fit construction allows for a complete range of movement with no chafing or mobility restrictions.
Plus, the fabric prevents moisture from soaking through the material and dries quickly. Seamless stitching also means you’ll avoid uncomfortable scratching and prevent chafing. A zipper lets you control your body temperature as you run.
One thing to note is that the men’s version is called the Explore while the women’s is the Comet. There are some minor style differences but otherwise, they are nearly identical.
- Allows for a wide range of movement
- ActiveDry tech acts as a powerful moisture barrier
- Works well as outer layer and base layer.
- Sizing runs small on Salomon products
Best Compression Baselayer
8. Under Armour ColdGear Armour Compression Mock
The Compression Mock from Under Armour has a tight, compression fit that provides a solid base of warmth and dryness. It’s made from a blend of 87% polyester and 13% elastane. Plus, flatlock seam construction prevents stitching from rubbing against your skin.
The base layer has 4-way stretch so you have freedom of movement while you run. Anti-odor materials will help prevent this shirt from smelling like yesterday’s dirty laundry.
While not a true compression shirt, it’s snug fit works well as a tight-fitting base layer to help keep you warm.
- Slim fit for easy layering
- No seams to rub against skin
- Anti-odor fight power
- Logo on the back breaks easily
Top Short Sleeve
9. Smartwool Merino 150 Short Sleeve
Not every base layer needs to have long sleeves. The Merino 150 has short-sleeves so it can be worn alone in summer or as a base layer under warmer gear during the winter.
The soft Merino wool is blended with a nylon core to help increase durability. Plus, flatlock seams allow for added comfort when wearing a backpack or additional layers of clothing. Overall, the shirt is breathable and lightweight.
The fit of the shirt is slim but not constricting. The material is 87% wool and 13% nylon, water-resistant, and comes with natural antimicrobial properties to help reduce odors.
- Soft Merino wool with a durable nylon core
- Short sleeves perfect for warmer temps
- Flatlock seams allow for comfortable layering
- Water resistant
- Tight, slim fit not usually ideal for casual wear
10. New Balance Q Speed Fuel Jacquard Long Sleeve
This long-sleeved base layer shirt combines comfort, ventilation, and safety. Unique New Balance dry technology pulls moisture away from your skin to keep you dry. Plus, polyester material and mesh side panels allow for consistent and comfortable airflow.
This shirt features 53% recycled polyester for a green design. The jaqard fabric helps to pull sweat away and keep you dry.
- Comfortable and warm polyester construction
- Mesh side panels allow for great ventilation
- Made with recycled fabric
- Includes no pockets or zippers