Base Layer for Running: 11 Cold-Weather Picks to Stay Warm

When it comes to cold-weather, the right base layer for running can keep us warm, comfortable, safe and even motivated to get out the door in the first place...
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Especially when temperatures dip below freezing, wind is howling and snow swirling.
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A base layer for running can help you manage weather and conditions when the going gets cold.
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What exactly is a base layer for running?
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Here's some advice from runner Brynn Cunningham + 11 base layer for running picks.

Here's the basics about base layers for running, they are...

• The first layer
• Meant to be worn next to the skin
• Like a second skin or long underwear

🔥Base layers come in various levels of warmth:

• Lightweight 
• Midweight
• Heavyweight/ thermal

And in a variety of fabrics:

• Wool
• Capilene
• Poly-blends
• Patented moisture-wicking materials, etc…
• But NEVER cotton - wet cotton, whether from sweat or the elements, is a surefire way to hypothermia and botched runs.

Many of the top running apparel brands offer base layer for running options giving runners a wide array of:

• Price ranges
• Sizes
• Fit
• Styles
• Colors, and...
• Fabrics to choose from

Planning some runs in colder weather? Check out these 11 base layer for running picks:

For assistance in determining your own size, here are the female wear tester’s measurements:

• Height: 5’ 3 ¾”
• Weight: 120-125 pounds
• Waist: 27.75 inches
• Chest/bust: 34 inches
• Hips: 34 inches
• Thigh circumference: 18.5 inches
• Inseam: 28 inches
• Typical shirt size: XS
• Typical pant size: 2, sometimes 0 if the brand runs large

The Patagonia Long-Sleeved Capilene Cool Daily Shirt, which I wear in size extra small, is listed in the Patagonia Baselayer section of their website, though it functions well as a stand-alone shirt, too.
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While I mostly use it as the latter, it comes in handy...

• As a lightweight base layer when I want a thin long-sleeve underneath a windbreaker...
• Or rain jacket during high winds or cold rain or during a mix of cloudy, rainy, wet, windy days in the high 40s to 50s. 

After all, I live in the same region as the ninth cloudiest city in the United States, right up there with Seattle and Portland, making a lightweight base layer a running wardrobe must-have.
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Because when it’s 50 degrees with zero sun and lots of elements, the real-feel temperature can bring on a chill quite quickly, especially on the trails.
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The fit: The waist is a bit wide (it does not hug the body), and the arms are a bit short, but I have long arms. 
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Still, the Capilene Cool Daily Shirt fits nicely under loose outer layers and even sweaters.

Another running wardrobe staple is a midweight base layer such as the Patagonia Capilene Midweight Crew, which I wear in an extra small. 
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It has a smooth outer finish, allowing for ease of layering, as well as elastic thumb holes, making it a cinch to wriggle into another shirt or outer layer. 

• For me and my personal body temperature/ sensitivity to cold, this base layer works best for the mid-30s to low-40s, a common temperature range where I live, especially if running in the early mornings or late evenings. 
• I can wear it alone on a sunny, mid-40s day, but mostly wear it as a base layer on colder days. 

The fit: The arms are a little bit longer than the Capilene Cool Daily Shirt, making it easier to slip into the elastic thumb holes when needed. I wear the Midweight Crew three seasons of the year. 

If you were to rate the Patagonia base layers reviewed in this article as warm/ warmer/ warmest, the Patagonia Capilene Thermal Weight Crew, which I wear in size extra small, would certainly be warmest.
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Winter running is a magical time of the year to get out and experience the world. 

• This shirt makes that experience not only possible but also cozy and inviting. 
• The thermal weight crew boasts the same smooth exterior and thumb holes as Patgonia’s Midweight Capilene, featured above, for ease of layering. 
• I wear this one when it’s below freezing and underneath my sweaters during the day, so that I’m half-way dressed when it comes time for a run.

The fit: The Capilene Thermal Weight sits slightly lower on the hips than the Midweight and is a little bit stretchier, always a plus. 

• Shop Patagonia Baselayers

A high neck base layer like the Ridge Merino Aspect Merino Wool High Neck Top, which I wear in size extra small, can...
 

• Amp up your confidence in the cold
• Allow you to bundle up, and...
• Get out in the elements with no fear of freezing

The Aspect is thinner than non-wool base layers but has all the warmth while possessing those much-loved merino wool qualities, including:

• Quick-drying
• Extreme softness
• Thermoregulation
• Odor resistance (I hang this up to dry and use many days in a row - it NEVER smells bad).

I wear the Aspect as a stand-alone shirt when it’s 30-something degrees and also as the first layer when it’s below freezing.
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Additionally, the high neck covers my entire face...

• All the way to the hairline if I wanted, not that I wear it that high, and can even sit and stay above my nose without slipping off while running. 
• Though I love a separate neck tube or buff, the high neck completely eliminates the need for any of those additional accessories, making getting dressed a cinch less complicated. 

Even more, the Aspect is multi-functional and versatile
 

• It can go from home to street to office to trail to errands with ease. 
• I like to put on at least some part of my running outfit at the beginning of the day, so that when I’m ready to hit the trails, I’m already partly dressed. 
• The Aspect is wonderful as a layer underneath a chunky sweater, dress, or jumpsuit, easing the transition from life to running. 

The fit: Sometimes my extra-small shirts have short arms, but not the Ridge Merino Aspect. 

• The sleeves cover half my hands, with thumb holes that are the same material as the shirt itself and essentially an extension of the shirt, as opposed to an elastic loop like the Patagonia Midweight and Thermal base layers. 
• As for the length, it sits below my hip bones, making it easy to tuck into pants to keep a draft from sneaking in.

Shop Ridge Merino

Because the Smartwool Classic Thermal Merino Base Layer Crew, which I wear in size extra small, is a hand-me-down that’s nearly 10 years old, I’m not sure if the shirt pictured here holds the exact same description as the current version listed on the website, but it’s pretty darn close.
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100 percent merino wool shirt. Regardless, I had to include it, because, despite its age, it’s a classic, 100 percent merino wool shirt, and aside from some staining and slightly saggy armpits from years of wear, it’s in good condition.
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As I mentioned, merino wool is a wonder fabric for high-output outdoor adventures like trail running, or even plain running, and you can’t beat it for its warmth.
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Once upon a time, I used to grab this favorite shirt for running on 50-degree days, deceived by the lightness of the fabric, only to get into the run to realize that I chose a thermal shirt, albeit one that felt too lightweight to be thermal.
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I’ve learned to reserve this one for colder days, 30 degrees or less, and I hope to hold onto it for another 10 years.
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The fit: Perfect: snug torso, long arms, stretchy.
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Shop Smartwool

A midweight base layer legging like the Patagonia Women’s Capilene Midweight Baselayer Bottoms, which I have in size small, works perfectly for a high-output activity like running.
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When worn underneath a rain shell or wind pants, the Patagonia Women’s Capilene Midweight Baselayer Bottoms regulates temperature well and keeps in the warmth without overheating.
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Keep in mind that I lean to the colder side...

• Some may find that wearing base layer bottoms for running is too much. 
• I like these for running in heavy rains in the high 30s or low 40s, when the trails are more like creeks than paths...
• Especially when worn underneath the Outdoor Research Women’s Helium Rain Pants or the Patagonia Wind Shield Pants.

The fit: I am usually in between a size small or extra small in bottoms, and while I went for small in the Patagonia Capilene Bottoms, sometimes I wish I would have purchased a size extra small, as the knees and thighs are baggy. 

• Yet, I’m afraid the smaller size would have been too tight around my calves. 
• This is more of a body-type issue, as the lower legs of base layers often fit well while the hips, butt, thighs and knees are too loose.
• Still, I like to sleep in base layer bottoms while camping, and for that, I want a looser fit, so I’m not willing to trade a too-tight lower leg for a well-fitted upper leg area. 
• Even more, I’d love to wear these as tights under sweater or hoodie dresses, but they are too saggy to look chic. Thus, they serve the purpose of a first layer under track pants or rain pants and as camping pajamas. 

Shop Patagonia Men and Women Baselayer

While my favorite pair of lightweight base layer bottoms are a discontinued size extra small Mountain Hardwear product, with nothing similar on their shelves, these extra small Smartwool ones are a close second. 

• They were given to me by a friend nearly eight years ago, making them at least 10 years old. 
• I’m not sure if they are exactly like the Smartwool Women’s Classic All-Season Merino Base Layer Bottom.
• But they are 100 percent merino wool and as durable as any Smartwool product I’ve ever owned. 
• Aside from a fraying waistline due to extreme wear and tear, they are in good condition, and I plan to wear them until they completely disintegrate. 

I use these much like the midweight and thermal pair of base layer leggings that I own: 

• Underneath the Outdoor Research Women’s Helium Rain Pants during a rainy, windy day in the mid-40s with sloppy trail conditions, or...
• The Patagonia Wind Shield Pants when it’s not so wet. 
• Furthermore, I like to wear lightweight base layer bottoms under joggers and pants while I’m working in my home office during the colder months, making these a multi-functional piece of running gear. 

The fit: Yep, extra small is the perfect fit. 

Smartwool knows how to do base layers, and the Smartwool Women’s Classic Thermal Merino 250 Base Layer Bottom, which I have in size small, is no exception. 

• They feel more like a soft pair of thick cotton leggings, even though they are 100 percent merino wool. 
• Their ability to thermoregulate proves that this is more than just a cozy pair of long underwear. 
• They work best when it’s 33 degrees with a mix of rain, sleet and snow and worn underneath the Outdoor Research Women’s Helium Rain Pants. 

The fit: They fit similarly to the Patagonia Midweight Baselayer Bottom (read review above) but are even baggier in the knees and hip area - perhaps you can see the loose fabric on the hips in the photo.
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But again, I wanted to be able to sleep in them during cold-weather camping, so I opted for a looser fit.
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Maybe one day I’ll find the perfectly fitting base layer bottom!
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Shop Smartwool

Nathan Reyes is the co-founder of WeeViews.
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He's game for some cold-weather running in Ohio with the right base layers.
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And in case you didn't know, he's also a running-sock  aficionado.

• Running Sock Obsession: Peek Inside This Runner's Sock Bin

Here's his base layer for running recommendation...

I tend to get pretty chilly this time of year, so I went for the Burton Men’s Midweight Base Layer Long Neck Shirt.
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Why? 

• It's heavier than what most of us are used to having wrapped around our bodies while running uphill in a hot, sweaty mess, but it sure does take on the cold while being active. 
• It’s also perfect for: coaching, volunteering or simply spectating a friend's Thanksgiving turkey trot.  

Runners will appreciate the feel on their skin as well as the ability to hide the neck and chin from the wind chill.
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When we leave the slopes, we tend to forget brands like Burton, who pioneered the outdoor performance gear industry, but I can’t help but like a heavier, warmer underlayer when my body heat lets me down.
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Shop Burton Men and Women Base Layers

David Moore is the co-founder of WeeViews.
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He still finds time to run when Ohio winter weather arrives. But he's happy to go with cross-training for triathlons, too.
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If you're wondering how to make running a regular part of a busy schedule, check out David's advice:

• Running Schedule: 5 Tips to Keep Up the Pace

Here's David's base layer for running picks...
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For assistance in determining your own size, here are the male wear tester’s measurements:

• Height: 5’7”
• Weight: 165 pounds
• Waist: 32 inches
• Chest: 40 inches
• Typical shirt size: M

I bought the REI Co-op Merino 185 Long-Sleeve Base Layer Top and Bottoms as a set.
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After comparing the Smartwool 250 line with teh REI Co-op Merino 185 line, I decided that for more than half the price, I’d take a shot with the REI Co-op and have had no complaints.  

• All things equal, I’m sure I’d rather have the Smartwool, but this $185 set has performed great and at around $125 less than the alternative. 
• I rarely wear a bottom layer during high output activities such as running, but the top has been great as a base in temperatures below freezing. 

Shop REI Co-op Men and Women Base Layers 

Share yours in the comments or create a WeeView and tell us more about your favorite base layer for running.