Updated:
Nov 14, 2025Warmth
Breathability
Durability
Comfort
Odor Resistance
Sustainability
Fabric(s)
92% polyester, 8% spandex
Fabric weight
129 g/m²
Weight
4.9 oz.
Variations
Crew
Pros
Cons
Patagonia Capilene Thermal Weight Zip-Neck
For this season's top models, see our guide to the Best Base Layers.
Despite its name, the Patagonia Capilene Thermal Weight Zip-Neck isn’t all that warm. Instead, it provides light to midweight warmth that's ideal for year-round wear. The Capilene Thermal is made from a lightweight fleece, Polartec Power Grid fabric, mixed with spandex for added stretch. Its loft traps warmth efficiently; in fact, it’s comparable to a 100% merino layer of the same fabric weight (129 g/m²).
I tested the Patagonia Capilene Thermal during a 15-hour climb of Mount Stuart in Washington’s Central Cascades. The day called for ten hours of walking and five hours of climbing a 2,500-foot ridge to an elevation of approximately 9,000 feet. I wore shorts on the approach, pants on the climb, and the Capilene Thermal throughout. While the weather ranged from 40 to 55 degrees Fahrenheit and my activity level oscillated from casual to fast, the Capilene Thermal maintained its Goldilocks all-day comfort. With this kind of versatility, this base layer is perfect for everything from summer days in the alpine to resort skiing in the winter, as long as you manage the rest of your layers well.
The Capilene’s Polartec fabric features a grid construction that creates open-air channels, providing outstanding breathability and moisture-wicking performance. The knit material helps lock in heat when it’s cold and lets it escape as your temperature rises. While climbing Mount Stuart in the Capilene Thermal, I remained comfortable both at rest and during the climb. When I did sweat, the fabric immediately wicked the moisture from my skin, drying faster than merino and without ever getting bogged down. All in all, this is a great base layer for any active pursuit, including climbing, ski touring, skate skiing, and shoulder-season running. For more on why we prefer synthetic over merino for high-output use, check out our article When A Merino Wool Base Layer Isn't the Answer.
Synthetic base layers are typically more durable than those made from merino. And while the Capilene Thermal does hold up relatively well, keep in mind that its thin construction is not as durable as thicker synthetic layers. Expect a bit of pilling, especially if you plan to wear it on its own (without a layer over it). We wouldn’t necessarily recommend it for particularly abrasive activities such as climbing, although it will get the job done in a pinch. But if you plan to primarily wear the Capilene Thermal under a mid or outer layer, it should last through years of use.
The lofted Power Grid fabric is luxuriously soft and airy. It doesn’t cling to your skin as much as tighter-fitting base layers, such as the Smartwool Intraknit Thermal. It’s stretchy, too, allowing you to move unrestricted while on the slopes, at the crag, or on the trails. Despite being synthetic, the Patagonia Capilene Thermal lacks that snaggy, plasticky feel of most polyesters; instead, it's more like a light gridded fleece, un-suffocating and cozy. I didn’t mind keeping it on at the end of the day for around-town and lodge activities.
The Capilene Thermal is coated in HeiQ Pure odor control, a silver ion-based antimicrobial solution that safely blocks odors while maintaining the fabric’s durability and breathability. It’s guaranteed to last the fabric’s lifetime, too. The technology works; we’ve found HeiQ to be about as good as it gets for synthetic base layers, although merino is still king for odor resistance. In our testing, the Capilene Thermal remained fairly odor-free and didn’t retain odors between washes.
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Longevity
Choosing durable outdoor gear and keeping it in use for longer is one of the best ways to reduce environmental impact. Our proprietary longevity rating assesses factors like overall build quality, materials, fabric denier, component durability, and real-world performance. A green check indicates that we expect the product to be long-lasting relative to its peers, a yellow check mark indicates average longevity, and a red X indicates a product that may have a limited lifespan.
Recycled Materials
Recycled materials are prevalent in outdoor gear, with nylon, polyester, wool, and down among the most common, but the composition varies widely. A green check mark indicates the product is made with a substantial amount of recycled materials (100% recycled or the core fabric that makes up most of the product is recycled), a yellow check means it contains a moderate to small amount of recycled materials, while a red X means there are no recycled materials in the product.
Bluesign Approved
Bluesign Technologies, based in Switzerland, operates a third-party textile management system that ensures materials are manufactured to strict environmental, chemical, and worker safety standards. A green check mark indicates a product is either a Bluesign Product (contains at least 90% Bluesign-approved fabrics and 20-30% Bluesign-approved accessories) or features a significant amount of Bluesign-approved materials. A yellow check mark means it uses some Bluesign-approved materials but less than the aforementioned category, and a red X means there are no Bluesign-approved materials in the product.
Responsible Manufacturing
This criterion evaluates a brand’s commitment to fair wages, safe working conditions, and reducing environmental impact through certifications and programs like Fair Trade Certified, Fair Wear Foundation, Worldwide Responsible Accredited Production (WRAP), and the Fair Labor Association, while also recognizing brands that manufacture primarily in the U.S. or Europe under strict labor and environmental regulations. A green check mark indicates a brand meets our responsible manufacturing criteria, while a red X means it does not.
Recycled and/or Reduced Packaging
Packaging can add significant waste to outdoor gear purchases, so many brands work to reduce its impact by using recycled materials, incorporating Forest Stewardship Council-certified paper products, and minimizing plastic and paper use. A green check mark indicates a brand uses recycled or reduced materials across all of its packaging, a yellow check indicates moderate or limited use of recycled or reduced packaging, and a red X indicates the brand does not make either of these efforts.
Resale and/or Recycling Services
Resale and recycling programs help keep outdoor gear in circulation longer and out of landfills, ranging from trade-in resale platforms that offer store credit to take-back initiatives that recycle products at the end of their usable life. A green check mark indicates a brand offers both resale and recycling programs, a yellow check mark indicates it offers one or the two, and a red X indicates it offers neither.
Carbon Footprint Tracking
This criterion evaluates whether a brand measures, reports, and works to reduce its greenhouse gas emissions using established frameworks such as the Higg Index, Greenhouse Gas Protocol, or The Change Climate Project. A green check mark indicates a brand publicly reports greenhouse gas emissions data, sets clearly defined reduction targets, and uses established tracking frameworks such as Higg or The Change Climate Project. A yellow check mark indicates the brand tracks emissions and outlines reduction goals but provides limited data, lacks science-based verification, or does not clearly report progress. A red X indicates the brand does not appear to track greenhouse gas emissions or provides so little information that its efforts cannot be verified.
Annual Impact Report
Annual impact reports provide transparency and accountability by outlining a brand’s sustainability efforts across areas such as material sourcing, greenhouse gas emissions, waste, water use, supply chains, and packaging. A green check mark indicates a brand publishes a detailed, brand-specific impact report that closely aligns with our sustainability criteria and leaves little room for ambiguity. A yellow check indicates a brand provides some relevant sustainability reporting but lacks detail in key areas or is covered only briefly within a parent company report. A red X indicates a brand does not regularly publish an impact report.
Tester: 5’5” 140 lb.
Size tested: Women’s small
Expect the Patagonia Capilene Thermal to fit true to size. I’m 5'5" and typically a women’s small, which is the size I reached for in the Capilene Thermal. It fit well. While Patagonia describes the Capilene Thermal as a “slim fit,” it’s nowhere near as snug as layers like the Smartwool Thermal Intraknit. Instead, it has a more casual silhouette, fitting easily under other layers while still being loose and stretchy enough for rigorous activities. If you’re broad in a given area (larger chest, shoulders, or arms, for example), the Capilene Thermal is accommodating, thanks to its thin and stretchy personality.
The North Face Summit Series Pro 120 ($100): Lighter and More Performance-Minded
The Patagonia Capilene Thermal Weight and The North Face's Summit Series Pro 120 are distinctly different base layers. However, both offer functional warmth and temperature regulation for varying weather conditions and activity levels. The Summit Pro 120 is slightly lighter and features a skin-tight fit that helps dissipate heat directly from your body to the fabric and out the other side. We’d reach for the two base layers in similar conditions and for similar activities, with the main differentiator being fit. For a deeper dive, read our Summit Series Pro 120 review.
Smartwool Intraknit Thermal Merino ($130): Breathable Merino
We generally reach for a synthetic base layer when we know we'll be working hard in the winter, but if there's one exception to that rule, it's the Smartwool Intraknit Thermal. The Intraknit isn't as lightweight or airy feeling as the Capilene Thermal, given its 53% merino wool construction and skin-tight fit, and it's not quite as durable either. However, with 45% polyester content and patterned mesh, it breathes well, dries quickly, and offers a wide comfort range that makes it great for start-stop activities and active use. We'll stick with the Capilene Thermal for mild conditions, but the Intraknit provides impressively breathable warmth for chilly days outside. For more, read our review of the Smartwool Intraknit Thermal.
Patagonia Capilene Midweight ($89): The Classic Capilene
Ignore the confusing naming: Patagonia’s Capilene Midweight is actually heavier than the Thermal Weight, with 147-gram 100% polyester material. It’s Patagonia’s classic base layer, available in crew and zip-neck versions. However, it’s not as versatile as the Thermal Weight: In our testing, the Thermal Weight is a bit warmer (despite its lower weight), yet more capable of flexing into milder conditions or withstanding sweatier internal conditions thanks to a more breathable build. In contrast, the Capilene Midweight feels outdated.
Don’t trust the name: This base layer provides light to midweight warmth and has a massive range to keep you comfortable whether you’re moving or at rest. However, it’s on the expensive side for a synthetic base layer and can’t match the warmth of merino.
Warmth
Breathability
Durability
Comfort
Odor Resistance
Sustainability
A wonderful option for high-output activities, the Summit Pro 120 is lightweight, breathable, and quick-drying. It also offers significant warmth for its thin construction, making it versatile for a range of temperatures and activity levels. However, not everyone will love the skin-tight fit.
Warmth
Breathability
Durability
Comfort
Odor Resistance
Sustainability
With a merino-polyester blend and mesh ventilation, Smartwool’s Intraknit Thermal is ideal for fast-paced activities in cold weather. It’s one of the only merino base layers we’ll wear when we plan to sweat. However, the price is high, and not everyone will love the skin-tight fit.
Warmth
Breathability
Durability
Comfort
Odor Resistance
Sustainability
Patagoinia’s Capilene Thermal is one of our favorite midweight base layers. It’s thin and airy, yet still provides moderate insulation, making it ideal for a range of activities. You can wear it by itself during chilly summer nights or under a layer or two for winter ski touring. The synthetic material is fairly durable, breathes well, and effectively wicks moisture. Additionally, the HeiQ Pure odor control works effectively, and the layer doesn’t retain odors between washes. While the Patagonia Capilene Thermal Weight is pricier than similar synthetic layers, it’s an incredibly versatile base layer that will serve you year-round.
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