Essential Outdoor Gear: Patagonia Capilene Cool Lightweight Review


The only baselayer you need.

What is Essential?
What makes something essential outdoor gear? When I did the Houdini Jacket review I was pretty sure I knew it when I saw it. As I worked through a few more gear reviews I started to wonder.

I review outdoor gear and clothing that I like. There’s a selection bias at work. If something doesn’t work for me, I’m not interested in writing about it. Partly this is an extension of my mother’s rule: “If you can’t say something nice, don’t say anything at all.”

Partly it’s because I’m reviewing gear from my own collection. I’ve spent years trying and rejecting outdoor equipment and clothing. Most of what I have by now has been thoroughly vetted. Especially after spending last summer in the Casita. I just don’t have anything laying around that’s junk. If I don’t like it, I get rid of it.

Some gear is essential. Houdini Jacket.

The upshot of this is that the reviews you’ll see on this site will be overwhelmingly positive. I like all this stuff. It’s all good.

That doesn’t mean that everything rises to the level of essential. For something to be essential it has to be great gear and more.

It has to be universal.

Love me some Rasslers…

Consider my favorite wet boot, the Astral Rassler. They’re the best water shoe I’ve found after years of searching. I use them for just about everything that involves getting my feet wet. But some people don’t get their feet wet. Not everybody needs a water shoe.

Essential outdoor gear has to be something that everyone can benefit from.

It also has to be versatile, something you can use for multiple outdoor sports and across different seasons. Obviously it has to be functional. Essential outdoor gear does the job it’s intended to do. Very well. In fact, I think it’s fair to say that essential outdoor gear should be so functional that it’s come to define the category. Like a Houdini jacket. Or a Whisperlite stove.

Whisperlite. Still the best.

Essential outdoor gear is an all-season, all-sport, category-defining product that everyone should buy.

If you sift through outdoor equipment and clothing using these criteria you begin to realize that there aren’t many products that rise to this level.

Patagonia Capilene Cool Lightweight baselayers do.

Versatile Baselayers
I wrote a giant post about baselayers back in March of 2018. It was part of a series of posts on a Simple Outdoor Clothing System that launched this site. In that post I outlined all the advantages and disadvantages of different materials and weights of next-to-skin clothing. Many of which I already own.

One of the reasons to write something is to learn. There’s something about putting words down that helps clarify your understanding of a topic. Doing the research to come to an informed conclusion. Testing your hypotheses.

I did a lot of testing as I was working up my posts on the various recommended layers in the Simple Outdoor Clothing System. I kept notes. Tried different combinations of layers in different conditions. I also looked back on experiences from backcountry trips. Everything from winter camping, to sea kayak expeditions, to Boundary Waters canoe trips. By the time I finished the series and summarized my conclusions I was down to one set of baselayers for all seasons. Capilene Cool Lightweight tops and bottoms. Winter, Summer, Spring and Fall.

Capilene Cool Lightweight
Patagonia has had an ultralight baselayer option for a long time. It was initially launched as Silkweight Capilene later it was re-badged as Capilene 1 and then Capilene Lightweight. The current name is Capilene Cool Lightweight.

Along with all these name changes has be a steady evolution in the fabric itself. The original silkweight fabric was heavier than the current Cool Lightweight. Much closer to what Patagonia now markets as Cool Daily (I reviewed the Cool Daily shirt here). This is a 3.7 to 4.1 ounce fabric with a smooth jersey knit. It’s similar to silkweight fabrics you’ll find in garments from other outdoor companies or in military surplus options.

Cool lightweight is much lighter. Almost half the weight. 2.3 ounce polyester with a partial or full recycled content. It also has a slight texture to it. The fabric is a double knit with a micro grid pattern that improves wicking performance.

The ultralight weight and fast wicking features of Cool Lightweight prompt Patagonia to place it in a specialty category aimed at hot weather active sports. In fact, at time of writing, you won’t even find Cool Lightweight under the baselayer category if you open that tab on the Patagonia site. It’s hidden away all by itself. I had to search to find it. Worse yet, it appears that the bottoms have been discontinued for Spring 2020 and will not carry forward into the Fall line.

This makes me wonder if Patagonia doesn’t really understand how baselayers work.

Active wicking fleece insulation changes the rules for baselayers.

Wicking Systems
That’s a pretty bold statement, considering that Patagonia introduced polyester baselayers to the outdoor market and has worked for years to promote the modern concept of layering for outdoor sports.

Of course, the idea of layering goes back much farther than the origin of Patagonia. The US military did extensive testing and development of layering systems as far back as World War II. In fact, there’s a good chance that Patagonia founder Yvon Chouinard was issued components of the US Army’s aging M-1951 cold weather uniform when he served in South Korea in the early 1960s. Maybe that’s where he got the idea.

Regardless of where the idea for layering came from, Patagonia has done done as much to educate people on the concept as any outdoor company. And they’ve continuously pushed innovation in wicking baselayers and insulation components.

Obviously they know how baselayers work.

That said, I do wonder if their approach to baselayers hasn’t kept pace with the opportunities created by the other technologies in their product line.

Products usually get dropped from the workbook because they don’t sell. There are lots of reasons this happens. Maybe it’s a bad product. Maybe the marketing approach doesn’t present it effectively. When I think about how good Capilene Cool Lightweight is, it makes me imagine the latter is more true than the former in this case. I suspect that if sales of the bottoms have dropped off to the point they’re not justified in the line anymore it’s because Cool Lightweight has been exiled to a dusty corner of the website. Pigeonholed as a hot weather baselayer rather than promoted as the versatile layer that it is.

Maybe this is inevitable. Products have to be marketed in a coherent way. If there are lots of options, they have to be positioned so they don’t compete with each other. And Patagonia offers lots of choices in baselayers.

Patagonia currently markets at least five different polyester wicking fabrics that could be used as baselayers: Cool Lightweight, Cool Daily, Midweight Capilene, Thermal Weight and Capilene Air, a wool blend. If you throw in Capilene Cool Trail, a heavier jersey weight material, you’re up to six. But let’s leave it out. Five is enough.

Do we really need all these different base layers?

I don’t think so.

We used to, but we don’t anymore.

Different weights of baselayers may have been useful in the past, but things have changed. The development of wicking fleece has largely made them superfluous. Patagonia’s R1 fabric, co-developed with Malden Mills, made heavier baselayers obsolete.


Insulation for outdoor sports used to be passive. Now it’s active.

Lightweight Fleece
The evolution of fleece. Conventional Polartec rear, Power Stretch center, Power Grid knockoff front.

In 1985 Patagonia launched both Capilene and Synchilla, a fleece bunting developed by Malden Mills and marketed under the Polartec label. Synchilla offered major performance improvements over the wool and synthetic pile insulating layers that were in use up until then. Synchilla was warm when wet, didn’t pill like pile, was faster to dry than wool, and was much lighter.

What Synchilla fleece didn’t do (and wool, ironically, did) was wick moisture as part of a layering system. In 1999 Patagonia launched R1 as part of it’s Regulator Fleece program and changed all that. Patagonia had an exclusive on the product for a while but it eventually was made available to other manufacturers as Polartec Power Grid.

Power Grid is fleece with wicking power. The fabric is a bi-component knit that mechanically wicks moisture from the inner surface to the outer where it spreads out for rapid drying. It wicks just like a baselayer.

[Polartec Power Stretch also actively wicks moisture. It has a hydrophilic nylon outer face that draws moisture away from the hydrophobic polyester fleece on the inside of the fabric. The nylon makes it slower to dry than Power Grid, but it’s another good option. Power Stretch is good. Power Grid is better. For a deeper dive on this topic check my post on lightweight fleece.]

Adding a wicking insulation layer to your clothing system completely changes the equation for your next-to-skin layer. If your insulation is passive, your baselayer doesn’t dry as quickly. It retains a bit more moisture as your body heat slowly pushes your perspiration through the passive fleece layer. With active wicking fleece insulation, the insulation layers pull moisture out of the baselayer. It dries much faster.

Faster drying means you need less volume of fabric next-to-skin to ward off a chill and manage moisture. This means your baselayer need not be any heavier than the lightest silkweight fabrics.

Put a different way it looks like this: under conventional fleece layers, ultralight baselayers can become saturated with perspiration and feel cool and clammy against your skin. Under wicking fleece like Power Grid, ultralight baselayers dry so quickly that they almost always feel dry next to skin. The difference is remarkable.

Don’t you need different weights of baselayers for different activities? Heavier for more sedentary activities? Lighter for more active?


What, exactly does this accomplish?

In fact, doesn’t this line of thinking contradict the whole concept of layering? After all, the idea of layering is to add or remove layers within your clothing system to adjust for different conditions and activity levels. Wouldn’t you want the lightest possible baselayer as the foundation of your layering system? That way if your activity level increased dramatically over the course of the day you could remove all but the lightest garments and reduce overheating and perspiration.

I’ll happily admit that my bias in outdoor gear is toward simplicity and minimalism. Sometimes this puts me at odds with conventional wisdom. But I think it makes sense. If you can buy one thing and use it for everything why wouldn’t you? Why spend more money to add more complexity to your outdoor clothing choices? With the advent of wicking fleece, heavier baselayers aren’t necessary. You can stick with the lightest wicking baselayer that you can find and layer over it as appropriate depending on conditions.

Which brings us back to Capilene Cool Lightweight.

As I mentioned at the top, Cool Lightweight is a feather-light 2.3 ounce double knit fabric. Solid colors are made from 100 percent recycled polyester. Heathers are made with 52 percent recycled. The fabric has a micro-grid texture that mechanically wicks moisture from the inner surface to the outer face. It’s astoundingly light and quick to dry.

Fabric is treated with HeiQ Fresh, a durable anti-odor treatment. I spent much of the summer wearing Capilene Cool Daily T-shirts that share this treatment and I’m impressed. I can stink up a synthetic baselayer as fast as anyone, and I’ve found I can get a day or two out of one of these shirts before it needs to be rinsed. Rinsing in fresh water resets the clock. Capilene Cool Lightweight dries so quickly that I would consider wearing it dry after a quick rinse.

HeiQ rates the durability of the Fresh treatment at 100 washes. This is a couple years of use if you wear and wash the garments weekly. Much longer with less frequent laundering. I suspect that cold water rinses do little to degrade the treatment, so frequent rinsing is probably the way to go if you want maximum longevity out of the anti-odor treatment.

Capilene Cool Lightweight is also treated with a fabric softener and wicking enhancer called  miDori bioSoft.  Surface treatments like this are common on all sorts of fabrics, from performance wicking layers to denim. In the past, many of these treatments were petroleum based and environmentally harmful. BioSoft is a plant based product that eliminates synthetic chemicals from the fabric finishing process.

Both HeiQ Fresh and bioSoft are certified under the Bluesign System. This independent industry monitoring system seeks to certify textile products that are non-harmful to the environment and are sustainably sourced. At time of writing Patagonia reports 80 percent of their product components as Bluesign certified.

Summer. Hot weather sun protection.

Next-to-skin Cool Lightweight feels cooler than any other fabric in my closet. The only thing that comes close are some of my hot-weather button-up shirts, but these don’t dry as quickly. I wear Cool Lightweight T-thirts to walk, hike and throw kettlebells every day. They manage perspiration, dry quickly and are more comfortable in hot weather than cotton T-shirts.

I spent our last winter in Madison trying different combinations of fleece and baselayers over the top of Capilene Cool Lightweight long sleeved tops and bottoms. It served as an effective baselayer in temperatures down to -25 F. Under grid fleece it managed moisture and dried rapidly regardless of my activity level.

Cool Lightweight is all-season gear.

Winter. There’s some Capilene Cool Lightweight under there somewhere.

There aren’t a ton of features to be found in a typical baselayer piece, but Patagonia manages to hit some nice design details. Both men’s and women’s tops have a slightly longer hem in the rear to help them stay tucked in. Both are cut to minimize chafing under a pack or harness.

Old vs New. Current Capilene Cool tops (front) have set-in sleeves, which reduce bulk under the armpit. Previous versions (rear) had raglan sleeves. Seams on shoulders moved forward to keep them out from under pack straps.

Previous versions of Capilene Cool Lightweight shirts had raglan sleeves which eliminated seams on top of the shoulder under pack straps. Sleeve design was switched in 2019 to an set-in seam, reducing fabric bulk under the armpit. Shoulder seams are now shifted forward to keep them out from under pack straps.

Cool Lightweight tops have underarm panels that remove seams that could chafe your armpits. Chafing is further reduced by the use of flatlock seams throughout the garments.

And there’s a little hang loop inside the collar. Nice touch.

The neck opening in the women’s top is a little larger than the men’s, likely a nod to fashion. The women’s top flairs toward the waist and has a couple V-notches at the hem so it looks good untucked.

Women’s top has a scooped neck, flares toward the waist and has a couple V-notch cutouts at the hem.

We used to get thumb loops in Capilene Cool Long Sleeve tops. These were a nice detail that helped prevent your sleeves from bunching up when you slid on an insulating layer. Now you’ll just need to grab the cuff when you layer up.

No loops for you! Current versions of the Capilene Cool Tops eliminate thumb loops.

Patagonia has discontinued the bottoms for now. Hopefully they’ll see the error of their ways and reintroduce them at some point. Until then, if you want a pair (which you should) you’ll need to search the discount sites and eBay to track them down.

As for the old stuff, here’s the skinny:

My men’s bottoms have a fly and hit slightly above the hips. Cristi’s Cool Lightweight bottoms have no fly, and feature a structured waistband that hits closer to the natural waist. The women’s bottoms also conceal the elastic waistband behind the face fabric so they look a little less like longjohns. Both have a gusseted crotch for comfort. All seams in the bottoms are flatlock sewn and positioned away from high wear areas.

Women’s bottoms had a structured waist that concealed the elastic waistband.

At 6′ 190 pounds I’m a size large in most things Patagonia. The large Cool Lightweight tops fit me perfectly. Close but not snug. There’s a little room to move inside them. Same is true of the bottoms–the fit is relaxed. I suppose there’s an argument to be made that baselayers should fit snugly but I haven’t found the relaxed fit of the Cool Lightweight pieces to be a problem at all.

The sleeves on the long sleeved top are plenty long for my 73″ wingspan. My inseam is 32″ and the bottoms hit at the ankle.

Cristi wears a large in both top and bottom as well. She’s 5’10” and has trouble finding tops with long enough sleeves. Not a problem here. As far as we can tell, the Patagonia size chart for the Cool Lightweight baselayers is right on the money.

I like to buy baselayer tops in light colors. That way they can double as sun and bug protection in warmer weather. The lightest color I was able to find in the men’s tops when I bought my long sleeve Cool Lightweights was Forge Grey. At time of writing Patagonia is offering several lighter colors for men that would do a better job in the sun. Women fare better. No shortage of lighter color choices there.

As for bottoms, may as well go with black. No need to match and they show dirt less.

Why Capilene?
I’m sure there are other options out there in ultralight baselayers. Back when I helped my friends rep Mountain Hardwear we had a couple tops and bottoms in the category. Some other company has to be making them. And there’s always the military surplus silkweight option. Why call out Capilene Cool Lightweight specifically?

First off, Patagonia more or less owns the technical baselayer category. They’ve been out ahead of wicking fabric innovation for the last 30 years. At times I wonder why other companies even try to compete. I’ve worn excellent baselayers from Marmot, Mountain Hardwear, NRS and others, but that doesn’t change the fact at Capilene is the brand leader in the category.

On top of this, Cool Lightweight is the lightest thing I’ve been able to find. It’s half the weight of conventional ultralight baselayer fabrics which means it dries faster and performs better than the other options out there.

Finally, I do like that Patagonia is trying to produce clothing that is less toxic and has a cleaner supply chain than conventional garments. In general, outdoor companies do a better job of this than many other garment manufacturers, but Patagonia has consistently pushed the issue. I think their advocacy has helped the entire industry to realign it’s manufacturing practices, partly by annoying the competition, and partly by proving the it can be profitable to improve the environmental footprint of your products.

Essential Outdoor Gear
Essential outdoor gear is an all-season, all-sport, category-defining product that everyone should buy. Capilene Cool Lightweight ticks all these boxes. It performs effectively in four seasons. It can be used for everything from birdwatching to alpine climbing. And there isn’t anything exactly like it available on the market from other vendors.

If you’re just getting started on your outdoor gear closet you can save yourself a lot of money and confusion by buying a Capilene Cool Lightweight longsleeve top and bottom right out of the gate. If you already have a closet full of outdoor clothes you can simplify your life and put them up on eBay after you buy Cool Lightweight. Regardless of what you do outside, they’re the only baselayer you need.

Of course, there are some caveats. If you want to get the most out of Cool Lightweight you have to layer it under wicking fleece like Power Grid or Power Stretch. And, for the moment, if you do want a pair of bottoms you’ll need to beat the bushes a little bit. It’s a shame. Another case of “if it’s good, they’ll cancel it.” Maybe they’ll bring them back. It’s happened before. Till then, we have the the interwebs.

Race you to the eBay.

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6 thoughts on “Essential Outdoor Gear: Patagonia Capilene Cool Lightweight Review

  1. I like your comment about keeping things that work and paring down your kit to the essentials.

    Been wearing Capilene as both a base layer and as a sun layer (in white) for warmer weather for several decades, love it!

    1. Thanks Eric. I have to believe that a lot of the complexity of choice in outdoor gear and clothing is about marketing more than utility. We don’t really need all this stuff. Keep it simple!

  2. Erik Pervin

    Hey Brian,

    I have been working through many of your posts and really enjoy them! I appreciate your thoughtful and thorough articles.

    Lately, I’ve been experimenting with cutting out baselayers altogether. I’ve been influenced by Andy Kirkpatrick’s discussion of softshells, notably the pile/pertex variety that incorporate wicking pile/fuzzy inside and a wind shell type outer. An R1 and a houdini mimic this, or there is the Buffalo Jacket, Proton FL, Rab offerings, and others mostly using Polartec Alpha.

    Full disclosure: I have not yet read your discussion of softshells, so maybe the answer is there, but what sets all of these jackets apart from the rest of the outdoor industry is that they are meant to be worn next to skin (according to Andy Kirkpatrick, and Buffalo), thereby eliminating the baselayer entirely.

    It seems like the logical extension of the argument you are making here, where if your insulation if sufficient and wicking, the role the baselayer plays diminishes, or may become entirely unnecessary. In my experience, this can be even more comfortable than wearing the Capilene Cool Lightweight underneath an R1, as the Capilene Cool Lightweight can sometimes feel a bit sticky or wet on my skin during more intense activity. I also run warm, and there are situations where I would be too hot layering anything over top of capilene cool and sweating, but the capilene cool on its own is uncomfortably cool (touring on windy days, my nipples and fore-arms freeze!).

    I’ve found that just wearing the R1 in the same conditions offers no apparent decrease in performance, I don’t overheat as easily since it is one fewer layer, and I keep the soft fuzzy fabric against my skin all day. Part of the comfort is because the fuzziness is constantly perceived as dry (the areas holding moisture are not in contact with my skin, as they might be with capilene cool lightweight), so I never feel chilled.

    This applies only to activities where it is cold enough to merit wearing the R1 as a baselayer, of course, and in warmer conditions or for very high exertion in cool temps, I may be wearing only the Capilene cool. Further, the new houdini air from Patagonia is very interesting and possibly even more versatile than the old houdini, making it a good layer to pop on top of capilene cool when an R1 would be too much.

    I’m wondering what your thoughts are on this? Part of what I like is the increased range of motion from wearing fewer layers, and just picking the right 2 layers for the job (baselayer insulation+shell), and then keeping a belay parka in the pack for when I stop moving. The shell can range from houdini, to thin softshell, rain jacket, to insulated softshell (gamma MX type), to full hardshell if merited.

    1. Thanks Erik. Great comment.

      You’re right. If it’s cold enough to run R1, you can use it as a baselayer on its own. Definitely wicks well enough and is very comfortable next to skin. I usually wear silkweight underneath, but I’ve worn grid fleece and Powerstretch next to skin under paddling clothing and it works really well. For paddlesports and immersion the ability of the fleece to rapidly drain water is a real advantage.

      The reason I like to run the silkweight as part of a system is because of it’s versatility. In warm winter temps I’ll be wearing silkweight next-to-skin with soft shell or wind shell over the top. If the sun is shining and I’m working hard, my shell jacket is coming off. If I get cold, I add insulation. Overheat? Strip it off again.

      So the silkweight will likely end up in my pack on a multi-day winter trip one way or the other, just to give me the option. I just put them on and forget about them.

      But, what you’re saying is right on the mark. If you’re going to be operating in temperatures that allow you to wear R1 all the time, there really is no point in layering silkweight underneath. You’ll probably stay drier and more comfortable with the wicking fleece as your next-to-skin layer.

      I don’t like insulated soft shells because I don’t think they’re as versatile as part of the system. There are times when I want the shell but I don’t want the insulation. If I have separate pieces I can mix and match to meet conditions. I REALLY don’t like soft shells with any kind of membrane because I sweat that stuff up like crazy. I think for a soft shell system to really work it has to be somewhat air-permeable and not totally (membrane) windproof.

      Thanks for joining the conversation!

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