In the typical three-layer clothing system, the midlayer is given the all-important insulating duties. As such, it is the one article of clothing you’re most likely to swap out depending on weather conditions. Is it bristling cold and dry? Grab your down jacket. Or, is it a slushy and moderately warm mess? Then a lightweight fleece or synthetic jacket might do the trick. All three types have their proper applications, and below we break down the top midlayer designs of 2020-2021. For more information, including the pros and cons of each form of insulation, see our midlayer comparison table and buying advice below the picks.
 

Best Overall Midlayer

1. Patagonia Nano-Air ($249)

Patagonia Nano-Air synthetic insulated jacket midlayerInsulation: Synthetic
Weight: 11.2 oz.
What we like: Supremely comfortable and excellent breathability.
What we don’t: Not quite as warm as down.

The Patagonia Nano-Air is special: it’s a super-soft, stretchy, and breathable synthetic midlayer that feels like a combination of a performance down puffy (minus the down) and your favorite sweatshirt. The result is a jacket that can be worn as a midlayer for winter sports or as an outer layer during the shoulder season or warm winter days. The stretchiness and breathability make it a favorite among backcountry skiers and climbers, and the soft feel is great for everyday use. And while previous versions of the jacket haven’t aged remarkably well (the face fabric has been prone to staining and piling), we’ve been impressed so far with the latest update, which features a more durable shell that is comprised mostly of recycled materials.

The Nano-Air can be your Swiss Army Knife layering piece, but keep in mind that its warmth is solidly middle-of-the-pack. This is a lightweight synthetic jacket and doesn’t offer the same warmth-to-weight as down fill. And although the latest version stuffs into its chest pocket, the Nano-Air is far from the most packable option here. However, it’s competitive in terms of weight at only 11.2 ounces, and the built-in freedom of movement—via stretch fabrics and an articulated design—is hard to beat. All in all, you won’t find a cozier midlayer, and we’ve become quite addicted to ours for everything from skiing and snowshoeing to travel... Read in-depth review
See the Men's Patagonia Nano-Air  See the Women's Patagonia Nano-Air

 

A Close Second (With More Weather Resistance)

2. Arc’teryx Atom LT ($239)

Arc'teryx Atom LT synthetic insulated jacketInsulation: Synthetic
Weight: 12.2 oz.
What we like: Great mix of mobility, warmth, and comfort.
What we don’t: Not as breathable as some of the newer synthetic options.

Arc’teryx has built its reputation on legendary shells and insulated jackets, and one of its biggest sellers is the Atom LT. Simply put, this is a top-notch midlayer that nails the essentials. You get an excellent balance of breathability and warmth, great mobility, and a just-right cut that fits most folks really well. A redesign for 2020-2021 includes a more durable face fabric and insulation, updated cuffs, and a longer hem, bringing it up to speed with modern options. And unlike many midlayers here, the Atom LT also works great as a standalone jacket with a decently tough, weather resistant shell. 

Compared to the Patagonia Nano-Air above, the Atom LT is less breathable due to its burlier shell and Coreloft Compact synthetic fill (although its stretchy fleece side panels ventilate pretty well). The Nano-Air also gets the edge in comfort thanks to the generous stretch from its shell and liner fabrics. But we do love the versatility you get with the Atom LT’s wind and water-resistant exterior, and its durable shell fabric will show much less wear over time. Keep in mind that Arc’teryx also makes the Atom in superlight (SL) and all-round (AR) versions, and for a down midlayer option, see the Cerium LT below... Read in-depth review
See the Men's Arc'teryx Atom LT  See the Women's Arc'teryx Atom LT

 

Best Budget Midlayer 

3. Columbia Steens Mountain 2.0 ($40)

Columbia Steens Mountain FleeceInsulation: Fleece
Weight: 16.6 oz.
What we like: Inexpensive and comfortable.
What we don’t: Limited warmth and questionable durability.

Sure, you can spend $300 or more on a midlayer and get some of the fluffiest down or techiest synthetic insulation on the market, but that doesn’t mean you have to. For days at the resort that aren’t super cold, you often can get away with a simple fleece like the tried-and-true Columbia Steens Mountain 2.0. Soft, inexpensive, and offered in a ton of sizes and colors, this is a very popular budget option. For $40 (and less on sale, which it frequently is), you get a no-frills midlayer with a surprisingly comfortable fit.

What are the shortcomings of going so cheap? The materials on the Steens Mountain 2.0 are very basic and the jacket has few features to speak of. It also won’t last as long as the higher-end fleece options on this list—the material is pretty soft and prone to pilling. Finally, the Steens is decently cozy but falls somewhere in the light to midweight category, meaning that the warmth it provides will be limited. For long and cold days at the resort, you’ll certainly want to go with a pricier down or synthetic midlayer. But for mild conditions and spring skiing with a baselayer underneath, the Steens Mountain 2.0 should get the job done.
See the Men's Columbia Steens Mountain 2.0  See the Women's Columbia Benton Springs

 

Best Down Midlayer

4. Patagonia Down Sweater ($229)

Patagonia Down Sweater midlayer jacketInsulation: Down
Weight: 13.1 oz.
What we like: Warm, versatile, and well-built. 
What we don’t: Fit is a bit boxy. 

Few jackets have stood the test of time like the Patagonia Down Sweater. First and foremost, down offers the best warmth-to-weight ratio of any type of insulation. This jacket doesn’t breathe as well as the synthetic options on this list, nor will it insulate as well when wet (down has a tendency to clump up and lose much of its warmth when damp). But for use as a midlayer in cold and dry weather with a shell over top, we love what the Down Sweater has to offer. You get premium 800-fill down for warmth, a high-end build that should last for many seasons of skiing and casual use, and classic styling that looks good just about anywhere. It’s quite likely that you’ll wear the Down Sweater under your ski jacket during the day and around town at night. 

As mentioned above, this jacket is inherently less breathable than synthetic jackets, meaning that it’s great for the resort but not a viable option for backcountry skiing. We also don’t love the fit of the Down Sweater, which is boxier than we would prefer to accommodate a wide variety of people and uses. But it’s hard to knock the versatility: this jacket makes a terrific midlayer, packs down decently small for travel and hiking, and looks the part. For less coverage and a lower price point, see the Patagonia Down Sweater Vest below... Read in-depth review
See the Men's Patagonia Down Sweater  See the Women's Patagonia Down Sweater

 

Best Ultralight and Packable Midlayer

5. Patagonia Micro Puff Jacket ($249)

Patagonia Micro Puff synthetic insulated jacketInsulation: Synthetic
Weight: 8.3 oz.
What we like: The light weight and packability of down in a synthetic jacket that insulates even when wet.
What we don’t: Fragile shell and not as breathable as the Nano-Air above.

Patagonia’s Nano-Air above is our top choice for resort skiing and daily wear, but at a bulky 11.2 ounces, it’s far from a minimalist midlayer. Enter the Micro Puff, which combines an extremely thin (10-denier) face fabric with Patagonia’s light and lofty PlumaFull insulation for a super cozy jacket that tips the scales at just 8.3 ounces. Designed for the Micro Puff, PlumaFill mimics down plumage, providing similar warmth, low weight, and packability of a down jacket in a design that still insulates when wet. The result is a high-performance midlayer ideal for weight-conscious pursuits like backcountry skiing and climbing.

Despite its technical prowess, it’s important to note that the Micro Puff is not for everyone. Unlike the Nano-Air and Atom LT above, it does not excel in the breathability department, nor do you get the stretch and sweatshirt-like comfort that makes many synthetic midlayers so easy to wear. If weight is not an issue—or if you plan to keep your jacket on all day—we’d stick with the options above. And while it functions well for midlayer use, the Micro Puff’s shell fabric is so fragile that we don’t recommend it as a standalone outer layer. But as the lightest synthetic jacket on our list (the down-filled Mountain Hardwear Ghost Whisperer/2 clocks in at the same weight but lacks the wet-weather assurance), the Micro Puff is hard to beat when weight and space are top priorities.
See the Men's Patagonia Micro Puff  See the Women's Patagonia Micro Puff

 

Best of the Rest

6. Arc’teryx Cerium LT ($349)

Arc'teryx Cerium LT down jacket iliad blueInsulation: Down and synthetic
Weight: 9.9 oz.
What we like: Premium build and super warm for the weight.
What we don’t: Pricey and won’t breathe as well as the synthetic jackets above.

The Patagonia Down Sweater above is a great crossover piece, but the Cerium LT offers a step up in performance. Weighing in at just 9.9 ounces—one of the lightest midlayers on this list—the Cerium is warmer than the synthetic options and packs down smaller than the Patagonia with its 850-fill power and thinner shell. And despite using mostly down fill, Arc’teryx made this jacket capable in wet conditions by mixing in synthetic insulation in areas most prone to moisture: the collar, shoulders, underarms, and cuffs.

Why is the Arc’teryx Cerium LT ranked here? At $349 for the non-hooded version, it’s expensive and overkill for use strictly as a midlayer. The Down Sweater offers comparable warmth, and the packability and added features won’t come into play for most resort skiers. Having said that, the Cerium LT is a superb down jacket that can be used for everything from skiing and backpacking to casual use (Arc’teryx looks darn good in the city too). An added bonus: we like the fit of this jacket, with is noticeably less boxy and more performance-oriented than the Patagonia. For an even lighter down midlayer, see the Cerium SL... Read in-depth review
See the Men's Arc'teryx Cerium LT  See the Women's Arc'teryx Cerium LT

 

7. REI Co-op 650 Down Jacket 2.0 ($100)

REI Co-op Down Jacket 650 midlayerInsulation: Down
Weight: 11 oz.
What we like: Great value for a down jacket.
What we don’t: Less of a performance option.

For those looking for a down jacket on a budget, we love what REI Co-op has to offer. Their original 650 Down Jacket was an undeniable value, and the “2.0” is even more impressive. Most notably, this version features soft-touch recycled nylon and reworked boxed baffling that gives it a distinctive look. It’s true that the 650 Down is a relatively simple jacket overall that lacks the fit, finish, and just-right cut of a Patagonia or Arc’teryx product, but it’s impossible to ignore the fantastic price of $100. In the end, the REI Down Jacket can go head-to-head in warmth and versatility with down sweaters that are double the cost from brands like Columbia and Marmot.

Keep in mind that this jacket isn’t a serious performance piece and is best for causal use and layering. The 650-fill down is a lower quality than the Cerium LT’s 850-fill above, and its non-ripstop nylon is more vulnerable to tears. In addition, this jacket lacks a hem adjustment, which is limiting for dialing in fit. However, for daily use, travel, and as a midlayer for resort skiing, you just won’t find a better deal. As an added bonus, the Co-op stuffs down into its left hand pocket, making it easily packable... Read in-depth review
See the Men's REI 650 Down Jacket 2.0  See the Women's REI 650 Down Jacket 2.0

 

8. Patagonia R2 Fleece ($169)

Patagonia R2 Fleece Jacket midlayerInsulation: Fleece
Weight: 13.4 oz.
What we like: The ultimate athletic fleece.
What we don’t: Limited water resistance (no DWR treatment).

In terms of performance fleeces, it’s tough to beat Patagonia’s R series. With multiple models of varying insulation and weather-protectiveness to choose from, our top midlayer pick is the R2, which hits a nice middle ground of warmth and breathability. This jacket is a hybrid of two types of fleece: a cozy high-loft fleece around the body and arms, and Patagonia’s more breathable and lower-profile R1 fleece under the arms and along the sides. The combination nets plenty of warmth for days at the resort but is great for movement and won’t overheat should you venture off-trail.

We also like fleeces as midlayers in terms of value. Patagonia apparel isn’t cheap in general, but the R2 at $169 is a nice step down in price from the synthetic and down jackets above. The major downside is that this jacket (and fleeces in general) does not block wind or guard against light precipitation, which limits its utility as an outer layer. For more weather protection in a relatively similar jacket, check out the R2 TechFace (also $169), which features a more robust face fabric with a durable water repellant finish.
See the Men's Patagonia R2 Fleece  See the Women's Patagonia R2 Fleece

 

9. Outdoor Research Refuge Air Hooded ($229)

Outdoor Research Refuge Air Hooded jacket midlayerInsulation: Synthetic
Weight: 16.8 oz.
What we like: A versatile and breathable midlayer that you can keep on all day.
What we don’t: Not as warm as other options but heavier; only available in a hooded version.

Outdoor Research has come out with a number of innovative midlayers over the years, and the Refuge Air is next in line. Like the Atom LT, Nano-Air, and Ventrix above, the Refuge Air combines the comfort, warmth, and temperature regulation of a layering piece with a durable and weather-resistant shell. But OR adds another wrinkle: exposed VerticalX Air insulation on the interior of the jacket (reminiscent of the discontinued Ascendant) for increased wicking and breathability. The result is all-day active insulation piece that is ideal for high-output activities like backcountry skiing, winter running, and climbing.

What are the downsides of the OR Refuge Air? Although it advertises a heavier insulation (75g) and clocks in a few ounces more than aforementioned jackets, in practice it offers noticeably less warmth. Further, the thin ripstop shell fabric and minimal water resistance means it’s not particularly reliable as a standalone piece. That said, the jacket’s breathable construction, minimal bulk, and trim fit make it an ideal choice for human-powered days when you might overheat in some of the warmer options above. And keep in mind that Outdoor Research also makes a standard Refuge ($220 for the hooded version), which offers more warmth while still managing to pack into its hand pocket. 
See the Men's Outdoor Research Refuge Air  See the Women's Outdoor Research Refuge Air

 

10. The North Face ThermoBall Eco ($199)

The North Face ThermoBall Eco jacketInsulation: Synthetic
Weight: 15.2 oz.
What we like: Good imitation of a lightweight down jacket.
What we don’t: Heavy and lacks the mobility of our top picks.

The ThermoBall Jacket from The North Face is one of the most popular and heavily marketed synthetic jackets ever. Made in conjunction with synthetic insulation masters PrimaLoft, ThermoBall technology uses small round clusters of PrimaLoft thermal fibers housed inside the jacket’s baffles, giving it the look and feel of a lightweight down puffy (and remember that synthetics insulate much better when wet). It still falls short in terms of warmth for the weight compared to high-quality down—just like every other synthetic out there—but is a pretty darn impressive effort overall and the jacket has been a huge success.

The ThermoBall Eco shares a similar design with the Patagonia MicroPuff above (a thin shell and down-mimicking synthetic fill), but it clocks in at almost twice the weight. In fact, it’s even heavier than midlayers like the Arc’teryx Atom LT or Patagonia’s Nano-Air, yet still lacks the durability and comfort that these sweatshirt-like jackets provide. And similar to many products from The North Face, one of our main sticking points with the ThermoBall is fit (the Ventrix above is one exception). Although the latest model is more form-fitting than previous versions, we’ve found that overall the jacket runs boxy (it’s also a little big in the arms). While this is fine for everyday wear and use as a layering piece at the resort, we prefer a performance cut and some stretch for better mobility... Read in-depth review
See the Men's The North Face ThermoBall  See the Women's The North Face ThermoBall

 

11. Ortovox Westalpen Swisswool Hybrid ($240)

Ortovox Westalpen Swisswool Hybrid midlayerInsulation: Wool
Weight: 11.6 oz.
What we like: A techy and low-profile midlayer for backcountry skiing. 
What we don’t: Purpose-built and lacking in everyday appeal. 

Ortovox is a German-based company with a focus on skiing, and their gear has a clear performance slant (you may also notice the fairly aggressive styling and colors). In the world of midlayers, the Westalpen Hybrid Swisswool is an interesting option for backcountry skiers in particular. This thoughtfully designed piece uses a stretchy grid material reminiscent of the Patagonia R series, but adds merino wool on the inside for comfort. In addition, you get panels of Swisswool insulation for warmth, water resistance, and breathability, all while keeping a low profile. The result is a techy yet functional midlayer for ski touring. 

In evaluating the design of the Ortovox Westalpen Swisswool Hybrid, it’s clear that this is a serious midlayer for the backcountry and lacking in everyday appeal. In addition, it’s quite light overall and the hybrid nature means that it won’t offer the same warmth as many of the other options on this list (it’s best for those on the go). That said, the jacket is more breathable than other wool midlayers like the Black Diamond Wool Aspect Hoody below, and we appreciate the company’s environmentally friendly slant. And for a similarly focused jacket with more weather resistance plus a hood, see the Ortovox Piz Palu. 
See the Men's Ortovox Westalpen Swisswool See the Women's Ortovox Westalpen Swisswool

 

12. Arc’teryx Atom SL Hoody ($229)

Arc’teryx Atom SL Hoody midlayer jacketInsulation: Synthetic
Weight: 9.2 oz.
What we like: Breathable; extremely lightweight and packable.
What we don’t: No insulation in arms and hood; not as warm as the competition.

Not everyone needs to be counting ounces, but for backcountry missions, weight savings is paramount. With 40-gram, breathable Coreloft Compact insulation placed only in the core, the Atom SL (“superlight”) stands out as one of the lightest and most packable jackets on our list. You don’t get the same amount of warmth as with other synthetic midlayers, but you do get a highly breathable design that will keep you comfortable as you move down the trail or skin track. In addition, the SL’s low-profile hood stows easily behind your neck and doesn’t get in the way while touring.

The Atom SL is a true niche piece—keep in mind that both the arms and hood of the jacket are uninsulated, making it more akin to a vest in terms of warmth (but with the bonus of weather resistance if you choose to wear it without a shell). Unless you run very warm during activity, we don’t recommend it for true winter temperatures. Further, if you’re willing to compromise on breathability, a layer like the Cerium LT will provide a lot more warmth and loft for a small .7-ounce weight penalty. But for a lightweight insulator that’s ideal for mild-weather use or high-output activities, the Atom SL deserves a look... Read in-depth review
See the Men's Arc'teryx Atom SL  See the Women's Arc'teryx Atom SL

 

13. Black Diamond Wool Aspect Hoody ($249)

Black Diamond Wool Aspect HoodyInsulation: Wool/synthetic
Weight: 14.9 oz.
What we like: All the benefits of wool in a high-performance jacket.
What we don’t: More technical features than you need for standard midlayer use.

Black Diamond is relatively new to the apparel scene, but their Wool Aspect Hoody caught our eye as a thoughtful and practical piece. While wool is an incredible insulator—warm (even when wet), breathable, and fairly packable—it’s a rare event to see it used in such a performance-oriented jacket. But we think the Aspect Hoody pulls it off quite well, combining the wool with a synthetic fiber for durability and washability, and adding stretchy side panels for great freedom of movement. Tack on a helmet-compatible hood and a mesh pocket that doubles as a stuff sack, and the Aspect has all the bells and whistles that we love in a climbing or backcountry skiing-oriented midlayer.

We’ve tested a number of Black Diamond jackets at this point, and find that their level of quality and durability consistently falls mid-pack. You don’t get the fit and finish of a jacket like the Patagonia Nano-Air, but you’re also paying significantly less (the hooded Aspect comes in at $249, compared to the Nano-Air Hoody at $299). Overall, while the Aspect Hoody isn’t our top pick for a standard midlayer—it would be out-of-place at the resort—we think performance-oriented athletes will love its technical features and hood. And due to its relatively svelte fit, it’s one of our go-to jackets for cold-weather rock climbing.
See the Men's Black Diamond Wool Aspect  See the Women's Black Diamond Wool Aspect

 

14. Patagonia Down Sweater Vest ($179)

Patagonia Down Sweater Vest men's blueInsulation: Down
Weight: 9.8 oz.
What we like: Warmth where you need it most.
What we don’t: Less versatile as an outer layer.

We all know by now that down is the warmest and most packable insulator, but for midlayer use in moderate conditions, a full down jacket can be too much. Enter the Patagonia Down Sweater Vest, which will provide ample warmth around your core without overdoing it. Like the popular full jacket version, the Vest uses premium 800-fill down, has excellent build quality, and looks great, too. And the vest weighs only 9.8 ounces, a nice 3-ounce drop from the jacket.

We love this vest for wearing under a shell or even as an outer layer for winter hiking and snowshoeing on a clear day. And of course, vests are great for casual wear in the fall and spring. One final piece of advice: if you go with a vest for a midlayer, make sure to choose a warm and comfortable baselayer. Obviously it matters more with your arms exposed.
See the Men's Patagonia Down Sweater  See the Women's Patagonia Down Sweater

 

15. Mountain Hardwear Ghost Whisperer/2 ($300)

Mountain Hardwear Ghost Whisperer 2 jacket navy blueInsulation: Down
Weight: 8.3 oz.
What we like: Great warmth-to-weight ratio; premium materials and great fit and finish.
What we don’t: Not as warm as the competition; thin shell lacks durability.

For years now we’ve turned to the down-filled Ghost Whisperer as our favorite ultralight insulator for missions when weight and space are at a premium. At only 8.3 ounces, it’s the lightest jacket on our list, and touts a significantly smaller packed size than the competition. Plus, you get the longevity of down (which stands the test of time better than synthetic insulation) and—updated for this winter—a slightly more durable shell made of 100-percent-recycled materials. In terms of warmth-to-weight ratio and ultralight performance, it doesn’t get much more premium than the Ghost Whisperer.

But pitting the Ghost Whisperer up against other down midlayers on our list is not necessarily comparing apples to apples. The Mountain Hardwear is stuffed with only 2.65 ounces of 800-fill down, compared to the much warmer Arc’teryx Cerium LT (3.14 oz. of 850-fill down and synthetic Coreloft) and Patagonia Down Sweater (3.4 oz. of 800-fill down) above. And while durability is less of a concern with a midlayer, the Patagonia Down Sweater’s 20x30-denier shell makes it much more of a versatile piece than the ultra-thin Ghost Whisperer (10D x 10D). Mountain Hardwear’s revered ultralight insulator certainly has its time and place, but its lack of durability and high price point mean we recommend it only for the most discerning adventurers... Read in-depth review
See the Men's MH Ghost Whisperer/2  See the Women's MH Ghost Whisperer/2

 

16. Arc’teryx Kyanite Hoody ($179)

Arc’teryx Kyanite Hoody midlayerInsulation: Fleece
Weight: 15 oz.
What we like: Great range of motion. 
What we don’t: A bit heavy and not as warm as a synthetic jacket.

For a serious performance fleece, we again turn to Arc’teryx and the versatile Kyanite. This jacket pretty much does it all: the midweight Polartec build works well as an active midlayer for backcountry skiing, yet it’s thick enough to wear as a standalone piece on the uphill and for climbing use in the shoulder seasons. We also appreciate the stretch of the fabric, which offers solid range of motion, and the trim fit means that you won’t have much in the way of bunching under a shell. 

What are the shortcomings of the Arc’teryx Kyanite? In general, fleece jackets are less warm and packable than comparable synthetic options, although you do save a bit in terms of cost. And at 15 ounces, the Kyanite is one of the heavier midlayers on the list, despite only providing moderate insulation. For a thinner fleece from Arc’teryx, the Konseal is a nice midlayer option for mild conditions and use as a cool-weather outer layer. 
See the Men's Arc'teryx Kyanite Hoody  See the Women's Arc'teryx Kyanite Hoody

 

17. Montbell Plasma 1000 Vest ($229)

Montbell Plasma 1000 VestInsulation: Down
Weight: 3.1 oz.
What we like: Unbeatable weight and packability.
What we don’t: Very thin shell fabric.

Montbell’s Plasma 1000 Vest can be summed up with two specs: 1,000-fill power down and a 3.1-ounce total weight. Starting with down fill, we consider 800-fill power to be premium quality, 900 is only offered from a few select companies, and 1,000 fill is nearly unheard of and just silly in terms of warmth to weight. And at 3.1 ounces all-in, the vest gives your core a surprising amount of cozy warmth at a weight that will make even the most discerning minimalists happy.

The very thin 7-denier shell on the Plasma 1000 is protected when worn as a midlayer, but it’s still a significant downside of the vest. Not only is the material crinkly when moving around, but it’s too delicate to trust without a shell overtop for most outdoor adventures. And even though the warmth-to-weight ratio is fantastic, the vest’s minimal 1.1 ounces of down only provides a modest amount of insulation. For extra warmth there is a Plasma 1000 jacket, which is viable for most summer backpacking and climbing trips, but clocks in at a “hefty” 4.8 ounces.
See the Men's Montbell Plasma 1000  See the Women's Montbell Plasma 1000

 

18. Smartwool SmartLoft 120 ($200)

Smartwool Smartloft 120Insulation: Synthetic (wool blend)
Weight: 15.6 oz.
What we like: Functional wool insulation and athletic fit.
What we don’t: Pricey; wool insulation isn’t all that warm.

Similar to the vest options above, the Smartwool SmartLoft 120 gives you warmth where you need it and range of movement where you don’t. All in all, we really like what Smartwool has done with this design, which includes a soft merino wool liner, SmartLoft 120g recycled wool insulation around the core, and a nylon exterior. Throw in a DWR finish and the result is an active midlayer, outer layer, or even baselayer that is comfortable, agile, and regulates your body heat quite well.

If you’re the type that runs cold, the SmartLoft 120 probably isn’t the midlayer for you. Wool is a good insulator and does a great job at not retaining moisture or stink, but even the 120-gram fill isn't all that warm for the weight (not to mention it’s only on the front of the jacket). But we still appreciate the design, which is very functional and creative compared to traditional jackets that are uniform in materials and thickness throughout. And we love the versatility: you can ski, hike, bike, and even hit the town in this jacket. For a warmer and more performance-oriented wool option, check out the Black Diamond Wool Aspect Hoody above.
See the Men's Smartwool SmartLoft 120  See the Women's Smartwool SmartLoft 60

 

19. Mountain Hardwear Monkey Fleece ($175)

Mountain Hardwear Monkey Man 2 midlayerInsulation: Fleece
Weight: 13.4 oz.
What we like: Fuzzy and comfortable, yet very functional.  
What we don’t: Polarizing looks.

The Monkey is an excellent performance fleece and one of our all-time favorite pieces of gear from Mountain Hardwear. First, it’s one of the softest jackets not just on this list but in general, made with Polartec's signature High Loft fabric. Aside from the high loft, this is not your bulky and casual fleece of yesteryear: it’s a slim-fitting piece that has built-in elastane for a forgiving stretch.

While the updated Monkey features a solid fleece rather than the previous open weave construction, we do find that the jacket is still on the thin side. Further, the air-permeable material offers little wind and no water protection. Whereas some midlayers easily pull doubly duty as weather-resistant outer layers (the Arc’teryx Atom LT or Patagonia Nano-Air, for example), you’ll almost always want to pair the Monkey Man with the added insurance of a shell. And although for the weight we’d prefer a bit more warmth (synthetic and down options are warmer), in terms of coziness, the Monkey Fleece cannot be beat.
See the Men's MH Monkey Fleece See the Women's MH Monkey Fleece

 

Midlayer Comparison Table

Jacket Price Type Insulation Weight Packable
Patagonia Nano-Air $249 Synthetic 60g FullRange 11.2 oz. Yes
Arc’teryx Atom LT $239 Synthetic 60g Coreloft Compact 12.2 oz. Yes
Columbia Steens Mountain 2.0 $40 Fleece MTR filament fleece 16.6 oz. No
Patagonia Down Sweater $229 Down 800-fill down 13.1 oz. Yes
Patagonia Micro Puff $249 Synthetic 65g PlumaFill 8.3 oz. Yes
Arc’teryx Cerium LT $349 Down/synthetic 850-fill down; Coreloft 9.9 oz. Yes
REI Co-op 650 Down Jacket 2.0 $100 Down 650-fill down 11 oz. Yes
Patagonia R2 Fleece $169 Fleece Polartec Thermal Pro 13.4 oz. No
Outdoor Research Refuge Air $229 Synthetic 75g VerticalX Air 16.8 oz. No
The North Face ThermoBall Eco $199 Synthetic ThermoBall Eco 15.2 oz. Yes
Ortovox Westalpen Swisswool $240 Wool 70g Swisswool 11.6 oz. No
Arc'teryx Atom SL Hoody $229 Synthetic 40g Coreloft Compact 9.2 oz. Yes
Black Diamond Wool Aspect $249 Wool/synthetic 60g Lavalon 14.9 oz. Yes
Patagonia Down Sweater Vest $179 Down 800-fill down 9.8 oz. Yes
MTN Hardwear Ghost Whisperer/2 $300 Down 800-fill down 8.3 oz. Yes
Arc'teryx Kyanite Hoody $179 Fleece Polartec Power Stretch Pro 15 oz. No
Montbell Plasma 1000 Vest $229 Down 1,000-fill down 3.1 oz. Yes
Smartwool SmartLoft 120 Jacket $200 Synthetic/wool SmartLoft (wool/polyester) 15.6 oz. No
Mountain Hardwear Monkey Fleece $175 Fleece Polartec High Loft 13.4 oz. No

 

Midlayer Buying Advice

Midlayer Insulation Types

Fleece
A skiing midlayer classic, the fleece jacket is a comfortable and affordable way to stay warm. In spite of what the name may indicate, fleece (or polar fleece) is a wholly manmade synthetic made up of petroleum products. Many new models are made of plastics such as recycled bottles, and through a rather impressive process, out spits a cozy and soft fleece. These jackets are wonderful as a midlayer for skiing thanks to their ability to resist absorbing moisture and their fast drying time. Additionally, cost is a big reason for choosing a fleece, even if they do have a tendency to pill up over time.

As far as warmth is concerned, fleece jackets are most often measured in terms of fleece weight. A 100-weight fleece—also referred to as lightweight, R1, or others, depending on the brand—is a thin and lightweight option that breathes very well but isn’t as warm. These are great for mild-weather skiing or backcountry skiers. 200-weight is the classic midweight and is the most popular choice for a standard fleece jacket, including the Mountain Hardwear Monkey Fleece and Patagonia R2 above. It’s warm enough for most cold days but has less of a tendency to overheat like the 300-weight option. Those heavyweights are for the truly cold days on the slopes—unless you’re someone that’s constantly cold.

Best midlayers (Patagonia R2 Fleece)
Patagonia's R2 uses a combination of lightweight and midweight fleece fabrics

Synthetic Insulation
Opting for a synthetic jacket will most often involve a slight step up in cost from a fleece but comes with reduced bulk and a more stylish, quilted appearance. And as an upgrade from down fill, synthetics continue insulating when wet. PrimaLoft was the first big name in synthetic insulation, but in recent years we’ve seen a variety of new blends come to market with a range of intentions. The North Face’s Thermoball and Patagonia’s PlumaFill, for example, seek to mimic the weight and compressibility of down, while other insulations prioritize breathability (like the impressive FullRange insulation used in Patagonia’s Nano-Air jacket). Depending on your needs, there’s likely a synthetically insulated jacket ideal for the job, and we particularly like highly breathable options for active resort or backcountry skiers.

Synthetic insulation is measured in grams, which is how much insulation a 1 x 1 meter section of the fibers weigh. Lightweight synthetics will have approximately 40 to 60 grams of insulation, and midweights are closer to 100 grams. Once you reach the midweight category, you are dealing with a very bulky jacket, which is why the 60-gram choice is so popular. It’s light and easy to move in, making it perfect as an all-around ski midlayer.

Patagonia Nano-Air (logo close-up)
Our top-rated Patagonia Nano-Air uses 60-gram synthetic fill

Down Insulation
The synthetic options above have never been able to match the heat retention of natural goose or duck feathers. There is simply no better way to stay warm than a down jacket, as long as you avoid heavy moisture—down will clump up and stop insulating when wet. If you really make an effort to stay dry with a bombproof shell, or for dry and cold conditions found in areas like Utah, Colorado, or parts of the East Coast, a down jacket is a perfect fit. On positively frigid days, an option like the venerable Patagonia Down Sweater remains a go-to choice.

In comparing down jackets, the two most important specifications are down fill power and fill weight. These are two independent measurements, but taken together they will give you an indication of how warm the jacket will be. To start, fill power is a measurement of the quality of the down clusters. Because down relies on loft to trap heat against your body, a jacket that requires fewer clusters to achieve the same amount of loft will be equally as warm but weigh less. As a result, you pay more for a higher fill power. Mid-range fill power falls in the 550-650 range, and high-end jackets will have 700+, reaching as high as 1,000 for some brands like Montbell. Fill weight is the next metric, and this is simply the total amount of down in the jacket, given in ounces. Now remember, weight isn’t the only indicator and should be looked at alongside the fill power, but it remains a very helpful number in figuring out jacket warmth.

Down Insulation (Patagonia Down Sweater)
The Patagonia Down Sweater uses high-quality 800-fill down

Wool
Many of our favorite baselayers are made with merino wool, due to its comfort, warmth, and ability to resist odor better than synthetic materials. And while this natural alternative isn’t seen as often in midlayers, it can go head-to-head with synthetics in terms of warmth (even when wet) and temperature regulation. But this all-natural insulator does have its downsides: wool can be more of a hassle when it comes time to do the laundry, and it lacks the warmth-to-weight ratio of down. As a result, we most often see it mixed in with a hybrid insulation design, like the wool/polyester blends seen in the Black Diamond Wool Aspect Hoody and Smartwool SmartLoft 120.
 

Important Strengths and Weaknesses

Warmth
Your preferences on warmth will depend on a number of factors, including where you ski and the conditions you’re willing to go out in, as well as considerations like if you use an insulated ski jacket or just a shell. Warmth will vary no matter the choice, but the most efficient heater is the down jacket. The clusters of feathers offer unmatched warmth relative to the weight of the garment. And choosing a higher fill-power option will have the best warmth-to-weight ratio.

Midlayers (fleece)
Fleece jackets fall at the bottom of the warmth scale 

Another natural insulator, wool offers cozy warmth and comes with the benefit of resisting odors better than other materials. However, wool’s warmth-to-weight ratio is less impressive, and it’s often on the expensive end of the spectrum. Next in line is synthetic insulation, which is sometimes referred to as a synthetic down because it was designed to emulate the heat-capturing abilities of the duck or goose clusters. While not as efficient in heating for the weight (some designs like the Patagonia Micro Puff are getting close), synthetic jackets are still a great choice for skiing in typical resort conditions.

A fleece jacket may be at the bottom of our warmth list, but that's not to say you can’t find a very warm fleece coat. It just takes a lot of fleece to get you there. And for many skiers (us included), a bulky jacket can interfere with the fun, which puts fleece at the bottom of our warmth scale.

Down: Excellent
Wool: Very good
Synthetic: Very Good
Fleece: Good

The North Face Ventrix (at camp)
Synthetic insulation mimics the heat-trapping abilities of down

Snow and Wet-Weather Protection
This category is where the down jacket struggles in relation to the other three. If your down jacket is poking out the bottom of your shell and you plant yourself in some wet snow (the Pacific Northwest variety comes to mind), the jacket’s ability to insulate will be compromised. One of the appeals in moving to synthetic, fleece, or wool insulation is the fact that they are still able to retain some insulating properties when wet (as a downside, wool can grow very heavy when saturated). Fleece is top of the class in terms of warmth when wet (due in part to the naturally hydrophobic nature of the polyester construction) and can also dry faster than synthetic fibers. However, many synthetic jackets will add a DWR coating to their shell to bead water, making them a far more suitable outer layer option than fleece. 

Fleece: Good
Synthetic: Very good
Wool: Good
Down: Not good (even hydrophobic down falls short)

Patagonia Nano-Air jacket water and snow resistance
Some midlayers are rugged enough to withstand wind and water

Breathability
Breathability is another strong suit of fleece, synthetic, and wool insulation. Overall, we give the edge to fleeces, which are naturally porous, and new models that have built-in stretch open up even more avenues for hot air to escape. Wool comes in a close second—this natural insulator excels at temperature regulation and, as a bonus, minimizes odor retention. Products like Arc'teryx's Atom LT are pushing synthetic jackets well into the high-performance world, but it can be hit or miss (and these jackets have a knack of holding stink). Unfortunately, down jackets are on the outside looking in here. Their supreme warmth retention doesn’t breathe nearly as well as the other two options (and working up a sweat can lead to the insulation getting wet and losing its ability to keep you warm).

Fleece: Excellent
Wool: Excellent
Synthetic: Varies, but can be excellent
Down: Good

Midlayers (breathability)
Backcountry skiing in the Patagonia Nano-Air

Weight and Compressibility
For the backcountry explorer that needs to throw a warm layer in their pack to stay comfortable at mealtimes, the down jacket remains the best choice. An 800-fill-power down jacket with a thin shell is capable of compressing down to the size of a grapefruit (although over-compressing for long periods can damage the feathers, so don’t go too crazy). Synthetics and wools (often wool/synthetic blends) vary quite a bit in compressibility. Lighter-weight options like the Patagonia Micro Puff and Arc'teryx Atom SL are reasonably compressible, but even these thinner jackets don’t stuff down as compactly as down fill. Fleece jackets aren’t really all that compressible, and throwing a mid or heavyweight fleece into a pack can make for a challenging endeavor.

Down: Excellent
Synthetic: Varies, but can be very good
Wool: Varies, but can be good
Fleece: Not good

Midlayers (Cerium LT stuff sack)
The Arc'teryx Cerium LT down jacket packs to a small size

Durability
This can be a challenging category to judge because there is a wide range in levels of durability. Insulated synthetic, down, and wool jackets vary from super-thin ultralight shells that are vulnerable to tears to tough jackets that you can throw on and forget about. In terms of the insulation itself, down and wool have long lifespans (and will continue to provide warmth as long as the shell of the jacket is intact), whereas synthetic materials tend to pack out over time. The durability of a fleece on the other hand is usually quite good. It’s possible to put a hole in a fleece by catching it on a sharp object or just wearing it thin, but those are relatively uncommon occurrences or take place over a long period of time.

The near-constant friction between your midlayer and outer shell jacket can cause abrasions and potential tears should a zipper catch the outer shell of your midlayer. In our opinion, because a couple extra ounces of weight are rarely a cause for concern while resort skiing, it’s worth it to get a more durable jacket. For insulated jackets, this means a tear-resistant fabric that is 20-denier (denier is a measurement of fabric thickness) or more. A jacket like the Patagonia Down Sweater has been popular for years on the slopes for having a great combination of sufficient toughness and minimal bulk.

Fleece: Very good
Down, Synthetic, & Wool: Varies, but can be good

Midlayers (Columbia Steens Mountain)
Fleece midlayers are generally quite durable

Getting a Proper Fit

Fit plays a very large role in an effective midlayer. Too much extra fabric and you will have bunching and general discomfort underneath your shell, and a jacket that’s too trim will restrict your mobility. It’s best to find that middle ground where you have complete freedom of movement without the jacket riding up, and no excess bulk. We prefer a jacket that has a non-boxy cut that allows us to wear a similarly athletic-fitting outer layer over the top. Arc'teryx in particular seems to consistently make jackets with this type of fit. As you're trying on midlayers, be aware of the normal pinch areas: around the waist, in the shoulders, and under the arm pits.

Midlayers (Arc'teryx Atom SL jacket layering)
Size your midlayer so you can layer a jacket overtop

Hood vs. No Hood

Deciding whether or not to opt for the hooded or non-hooded version of a midlayer might seem like a relatively inconsequential decision, but it’s actually deserving of some thought. For the most part, we prefer a non-hooded midlayer, particularly when we know we’ll be layering it under a hardshell or ski jacket. A hood is prone to bunching up behind the neck under an outer layer, and it can be cumbersome to don both midlayer and shell hoods at the same time. Further, if you’re like us and participate in activities where you wear a helmet (skiing, climbing, biking, etc.), keep in mind that most midlayer hoods are not helmet compatible.

But there are a few scenarios where we love a hooded midlayer. For one, if we are wearing a helmet, a svelte hood worn underneath can provide a good deal of warmth for both the head and neck, and will prevent snow from entering the jacket at the collar. Second, if we think we’ll be wearing our midlayer as an outer layer (which we often do with jackets like the Arc'teryx Atom LT or Patagonia Nano-Air), we love the extra warmth and protection of a hood. In the end, the decision of hood vs. no hood will come down to one of personal preference, and it’s important to know how you’ll be using your midlayer when considering your needs.

Midlayers (hardshell and hood)
When paired with a shell, the hood of a midlayer can get in the way 

Midlayer Jacket Features

Midlayers are fairly simple pieces, especially considering they’re meant to hide under your weatherproof outer layer. Feature sets are often limited to pockets, thumbholes, and hoods (which we discussed above). It’s true that most folks don’t use the pockets of their insulating layers on the slopes or in the backcountry all that often—it’s a pain to have to unzip a couple layers. However, midlayers are a classic choice for daily use, so don’t dismiss pockets completely. And if you’re eying a very technical piece that goes without pockets and you plan to use it around town, you may want to reconsider. Case in point: a more all-around choice may be the Patagonia R2 jacket (which features three total pockets) as opposed to the dedicated lightweight (and pocket-less) Rab Paradox Lite.

REI Co-op 650 Down Jacket (hand pockets)
Using the hand pockets on REI's 650 Down Jacket 2.0

Performance midlayers occasionally will have thumbholes built into the sleeves. While serving as an opening for cold air to sneak in when not in use, the openings work well for keeping the sleeves in place during high effort activities or when taking on and off layers. User tip: if you’re eyeing a jacket that has this feature, we recommend checking to make sure the fabric around the thumbhole has some stretch so it doesn’t feel like your thumbs are being yanked around every time you extend your arms.
 

Don’t Forget Your Baselayer

If you’re like most folks, you spend a lot of time picking out the perfect shell, then move to your insulating options, and finally just grab a baselayer willy-nilly. Trust us, this is a poor methodology. As the layer that’s next-to-skin, a baselayer is at the core of moisture wicking, temperature regulation, and a number of other essentials. If you have a crummy baselayer, all the fancy tech in your mid and outer layers will be nearly worthless. Top materials include merino wool for its excellent temperature regulation and odor prevention, and synthetics are quite good at drawing moisture away from your skin. Check out our top baselayer picks to see which ones stand out as best.
Back to Our Top Midlayer Picks  Back to Our Midlayer Comparison Table

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