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Midlayers are arguably the most versatile piece of our kit. Our team of three — a backpacker, skier, and climber — tested five midlayers for 50 days, from Colorado to Alaska and from packrafting to day hikes. Our most recent testing round saw two high-alpine athletes, Senior Editor Nick Belcaster and Contributor Bergen Tjossem, challenge high-breathability layers above treeline.

We’ve tested a slew of midlayers: full-zip jackets, hoodies, vests, and puffies plus lightweight and ultralight layers. Below are our best picks for year-round, with all-around solid fleece options like the Patagonia R1 Thermal to budget-wise layers like the REI Co-op Flash Hyperstretch.

Our multi-sport experts have layering needs that span the spectrum, and we’ve been testing for this guide since before 2021.

Editor’s Note: We updated our Midlayers guide on May 19, 2026, to add the Mountain Hardwear AirMesh Hoody and Montane Fortes Lite, two layers that prioritize breathability but with different takes. We also updated our testing information to reflect new rating requirements and metrics.


Rating Details

Warmth 9/10
Breathability 8/10
Durability 8/10
Style 7/10

Specifications

Style
Fleece
Material
6.5 oz. 91% recycled polyester/9% spandex flat-faced Technostretch fleece
Insulation
N/A, grid fleece
Weight
15.3 oz.
Pockets
Two

Pros & Cons

Pros

  • Warmest version of the R1 fleece
  • Face fabric is smooth and tight-knit, shedding flurries well
  • Microgrid fleece is warm and plush
  • Nice, snug hood
  • Wide size range

Cons

  • Not the most breathable option for high-output activities
  • Pricier than normal R1 fleece
Mary Murphy

The Quick & Dirty: The warmest R1 yet, featuring a wind-shedding face and plush microgrid interior. It excels in freezing alpine stop-and-go use, though it may overheat during high-output trail runs.

The R1 has a storied history in the Patagonia lineage, and another sibling has been added to the set: the Patagonia R1 Thermal Full-Zip Hoody ($219). This ‘thermal’ cut aims to be the warmest of the bunch, and having worn all four different styles, we can confirm that it nails the effort.

The main differences between the Thermal R1 and the rest of the fleeces include a tight-knit face fabric that cuts through the wind and a grid fleece arranged in a much closer-spaced configuration to really bump up the BTUs. We’ve used this piece as an active insulation layer while climbing 10,000-foot volcanoes in the Pacific Northwest, and it has enough warmth to get us to the summit and back.

Besides the warmer fleece, we found the cut to be typical of Patagonia (a bit boxy in the torso but well-fitting), with sleeves at just the right length for tucking into the thumb loops from time to time. The hood can be run underneath a helmet, and you also get a second chest pocket in this R1 — very slick.

At higher outputs, the R1 Thermal will hit a breaking point where it’s just too toasty, which is when we reach for something with a looser weave like The North Face FUTUREFLEECE or R1 Air. The wind will cut through both of these midlayers, but if it’s just not that cold ambiently (or you’re pumping out the heat), they can balance the scale well.

You also won’t quite get as much static warmth out of the R1 Thermal as you will with a synthetic puffy like the Arc’teryx Proton or Patagonia Nano Puff, but the benefit of going with a slightly thicker fleece is that your insulation jacket can be lighter. For most of our winter layering systems, this fleece fits in perfectly.

Rating Details

Breathability 7.8/10
Durability 7.5/10
Wind & Water Resistance 6/10
Packability 6/10

Specifications

Weight
11 oz.
Fit
Athletic
Fabric
54% recycled polyester, 35% nylon, 11% spandex
Density
Light to Midweight
Special features
Zippered hand pockets, drawcord hem

Pros & Cons

Pros

  • Stretchy
  • Slightly longer length with drawcord hem
  • Affordable
  • Hood stays on while running

Cons

  • No thumbholes
Mary Murphy

The Quick & Dirty: A budget-friendly, high-stretch fleece with a smooth face and a slightly longer cut for layering. It offers versatile warmth, though it lacks technical features like thumbholes.

A good facsimile to the R1 Thermal — for a good bit less — the REI Co-op Flash Hyperstretch Fleece Jacket ($100) checks most of the boxes we’re looking for in a midlayer. Warm enough, breathable when you need it, and stretchy to move with you. For less than a Benjamin, the Flash Hyperstretch does it all on the cheap.

Unlike the R1, the Flash Hyperstretch adds a few hand-warming pockets, which makes it better suited as an outer-facing layer. The longer torso length and drawcord cinch at the hem also aid in this effort, meaning you won’t have to rely on another jacket to keep errant breezes at bay.

The built-in stretch is also a notch above other fleeces we’ve tested, and that 11% spandex in the weave is put to good work when reaching high overhead. Unfortunately, the budget cuts are apparent when you do this, as there are no thumbholes in the Hyperstretch. A small price to pay, we’d argue, as the fleece leans a bit more casual, and the absence makes sense here.

The hood, we found, is a bit too accommodating — almost like a sweatshirt hood, and won’t be quite as sportif as pieces like the FUTUREFLEECE from The North Face or NW Alpine Black Spider Hoody. Still, it’s forgiven for the ‘all-around’ bent on the Flash Hyperstretch. We enjoy wearing this jacket everywhere from bumping around town to winter runs, and for the money, that’s impressive versatility.

Rating Details

Warmth 6/10
Breathability 8/10
Durability 7/10
Style 7/10

Specifications

Style
Fleece hoodie
Material
124 g/m² Teijin Octa FUTUREFLEECE — 55% polyester, 45% recycled polyester
Insulation
Grid fleece
Weight
6.2 oz.
Pockets
One

Pros & Cons

Pros

  • Octa fleece is highly breathable, but holds warmth well when under a layer
  • Extremely lightweight
  • Versatile layering option
  • Stretchy material is easy to move in

Cons

  • Not enough pockets
  • No wind resistance
  • Thumb loops are a little fragile
Mary Murphy

The Quick & Dirty: An ultralight layer using hollow yarns to trap heat while maximizing airflow. Highly breathable and packable, it’s the ideal layer for high-effort ski tours and winter training.

An entire sub-genre of loose-knit fleeces has sprung up in recent years, with notable tech in the form of Polartec Alpha Direct. The Octayarn fleece used in The North Face FUTUREFLEECE Full-Zip Hoodie ($190) is another take on the uber-breathable fleece, and when pushed to the limit on high-output ski tours or runs this winter, we found it well made the grade.

The FUTUREFLEECE fits more snugly than many fleeces, which helps to retain your hard-earned warmth between the uniquely bundled piles of yarn. The spaces between these bundles are quite thin, and allow for more air transfer when you really need to vent heat. While huffing up skin tracks in Colorado this spring, we found this hoodie to be the perfect weight.

Side-by-side, we found that the Octa fleece felt sturdier than Alpha Direct pieces, with an ultrathin outer face that helped keep the FUTUREFLEECE from being snagged on branches. All loose-knit fleeces are going to feel a bit fragile, but with the fleece yarns facing the interior of the jacket, there’s a good bit less to get caught on.

This fleece’s features are otherwise light, with a single chest pocket taking up slim real estate and thumb loops on the sleeves. The Summit Series from The North Face is all about high-alpine efficiency, so no love is lost here from us. Still, if a few dialed chest pockets are on your wish list, the Patagonia R1 Thermal is ready for action.

If you’re after a more summer-weight active fleece, consider the Senchi Alpha 90 Hoodie or Mountain Hardwear AirMesh Hoodie — both lighter weaves that work great at a hiking pace. For a wider range of conditions, however, the FUTUREFLEECE is our pick.

Rating Details

Warmth 8/10
Breathability 7/10
Durability 8/10
Style 8/10

Specifications

Style
Synthetic hoody
Material
Fortius Air 20 face fabric; 20D Toray liner
Insulation
PrimaLoft Gold 80 gsm torso, 60 gsm hood
Weight
14.6 oz.
Pockets
Three

Pros & Cons

Pros

  • Exterior is highly abrasion-resistant
  • PrimaLoft Gold is high-quality insulator, and is body mapped with different weights used in torso/arms
  • Hand-warming pockets are placed higher to avoid climbing harnesses
  • Helmet-compatible hood

Cons

  • Has an upper limit for breathability
  • Expensive
  • No thumb loops
Mary Murphy

The Quick & Dirty: A premium synthetic puffy balancing air-permeable fabric with body-mapped PrimaLoft Gold. It’s engineered to dump heat during movement while remaining warm enough for standalone use.

While the Atom line gets all the glory, we think that the Arc’teryx Proton Jacket ($350) is a slightly better synthetic midlayer from the brand. Styled as a more mountain-forward piece, the Proton is a bit warmer, uses a nicer synthetic fill, and cuts through the cold wind better. For a synthetic puffy, it’s tough to do better than this.

We’ve worn our Proton for more than 5 years now of constant use, and while it’s packed out some, it’s still going strong. The only other wear we’ve noticed has been the chest pocket zipper giving up the ghost and the logo wearing away. The price is undeniable here, but it pays out dividends in durability.

The 80 gsm PrimaLoft Gold used throughout the Proton makes it a notch warmer than the standard Atom (which uses 60 gsm), and compared to quilted synthetic jackets like the Patagonia Nano Puff, we tend to prefer sheet-style synthetic pieces like the Proton, as they retain more warmth without the losses associated with stitch lines.

Unlike the Atom (which uses underarm fleece panels to dump moisture), the Proton uses a more breathable Fortius Air 20 face fabric material to remain breathable. We found that in truly cold winds, the fleece panels on the Atom would let too much breeze through, while the Proton lets in just enough.

Ideal as a static warmth piece for shoulder season endeavors — or even an active piece for cold alpine climbing — the Proton has a dedicated spot in our closets.

Rating Details

Warmth 7.5/10
Breathability 9/10
Durability 8/10
Style 7/10

Specifications

Weight
12.9 oz. (men’s size M); 10.9 oz. (women’s size S)
Fit
Athletic
Fabric
100% recycled polyester fleece
Density
N/A
Weather resistance
No weather treatment
Pockets
Two handwarming, one on chest

Pros & Cons

Pros

  • Super-breathable zig-zag grid fleece
  • Lightweight
  • Wide range of sizes
  • Cozy on-skin feel with snug fit

Cons

  • Not very much static warmth
  • Wind resistance isn't great
  • No thumb loops
Mary Murphy

The Quick & Dirty: A technical zig-zag knit fleece designed specifically for moisture management. It’s breathable and soft, but its open-weave structure offers little resistance against breezes.

The Patagonia R1 Air ($189) is a standout technical fleece for both in-bounds and backcountry skiing, offering the highest breathability in the R1 lineup. Its unique zig-zag knit creates channels that dump heat rapidly during high-output skin tracks, yet it retains enough loft to provide a comfortable buffer under a hardshell while riding the lift. Unlike the minimalist FUTUREFLEECE, this is a more well-rounded layer that transitions seamlessly from spring touring to mid-winter resort laps.

The “Air” construction excels during quicker-paced mountain activity because it allows moisture to escape without passing through a dense face fabric. We tested it through high-vert Sierra tours and cold granite approaches, where it consistently kept us from wetting out from the inside. When the wind picks up on an exposed ridge, the R1 Air fits perfectly under a light shell, and its scuba-style hood is specifically designed to sit flush under a ski helmet.

For in-bounds convenience, the R1 Air features two hand-warming pockets and a low-profile chest pocket, ideal for stashing chapstick or a ski pass. The athletic, close-to-body fit ensures it stays tucked into your bibs or under a harness without bunching, while the high-stretch fabric provides total mobility for technical descents.

While its open-weave structure requires a wind-resistant outer layer to maintain warmth in a breeze, the R1 Air remains one of the most versatile pieces in a 2026 ski kit. Whether you’re huffing up a backcountry peak or grabbing an après-ski coffee, this fleece delivers the perfect balance of technical airflow and casual comfort.

Rating Details

Warmth 7/10
Breathability 8/10
Durability 6/10
Style 8/10

Specifications

Style
Fleece
Material
69% merino wool, 15% recycled polyester, 13% nylon, 3% spandex (body); 51% recycled polyester, 41% merino wool, 8% lycra (grid fleece)
Insulation
N/A, grid fleece
Weight
1 lb. (men's medium)

Pros & Cons

Pros

  • Very cozy merino grid fleece material
  • Smell-proof for longer
  • Smart thumb hole design

Cons

  • Chest pocket is a bit snug for modern phones
  • More expensive than comparable synthetic grid fleeces
Mary Murphy

The Quick & Dirty: A merino-blend fleece that combines the odor resistance of wool with the durability of synthetic fibers. It offers a premium feel for cold-weather layering, though it is heavier and slower to dry.

The Ridge Merino Cloudripper ($160) stands out in a sea of synthetic-heavy midlayers, proving natural fibers still belong in a high-alpine kit. While most brands chase hollow-core yarns, Ridge Merino doubled down on a heavyweight 265 gsm merino blend that is a cozy hug to wear. After a winter of testing this piece through damp Cascade temperatures, we were won over.

The magic lies in hybrid construction, blending merino’s thermal regulation with recycled polyester’s durability. On the skin track, the wool interior managed micro-climates far better than a traditional grid fleece. It lacks that initial chill when you start sweating, and even during a high-output climb while ski touring, the fabric stayed remarkably dry to the touch, wicking moisture without the immediate funk associated with full synthetics.

In terms of features, the Cloudripper is refreshingly intentional. The scuba-style hood is a highlight, fitting snugly under a climbing or ski helmet without bunching. You get two generous hand-warmer pockets and a zippered chest pocket that’s just large enough for modern phones. Low-profile thumb loops didn’t interfere with our glove gauntlets, a small but critical win during transitions in a blowy parking lot.

The athletic fit layers perfectly under a hardshell like the Arc’teryx Beta AR. Because the fabric is beefier than an R1 Air, it fills dead air space effectively, providing a noticeable bump in static warmth during lift rides. That density comes with a weight penalty; at 17 ounces, it isn’t for the ultralight crowd, but for anyone valuing durability and a soft-to-skin feel, the tradeoff is easy to justify.

Ultimately, the Cloudripper wins on versatility. While we spent most of our time thrashing it against granite and spindrift, it doesn’t show it besides some minor pilling. If you’re tired of crunchy synthetics and want a midlayer that smells better after a three-day trip, this is the one.

Rating Details

Warmth 7/10
Breathability 7/10
Durability 8/10
Style 9/10

Specifications

Style
Puffy jacket
Material
100% recycled polyester with DWR
Insulation
60 g PrimaLoft Gold Eco
Weight
11.9 oz.
Pockets
3

Pros & Cons

Pros

  • Stylish design looks good in the mountains and around town
  • Highly compressible given how warm it is
  • Slippery fabric makes layering easy

Cons

  • Extensive stitching adds some breathability but also allows rain to soak insulation faster
  • A little heavier than similar lightweight layers
  • Loose-fitting cuffs often let some heat escape
Mary Murphy

The Quick & Dirty: A classic synthetic puffy using 60g PrimaLoft for reliable static warmth and windproofing. It’s packable and works well around town, though it lacks the breathability required for high-exertion mountain use.

Over the years, the Patagonia Nano Puff ($229) has garnered nothing but praise. The size, style, and color options are varied, the insulation is warm, and the jacket itself is packable and lightweight. And unlike with down puffy jackets, you won’t be leaving feathers in your wake.

There’s a reason the Nano Puff has been in stores since 2010. And while it’s always been a bestseller and a staple in our wardrobe, there have been improvements, such as the 100% post-consumer recycled insulation. Like a good cheese, you could say the Nano Puff only gets better with age.

The lightweight and synthetic-insulated Nano Puff is windproof and water-repellent, boasts a standard 60 gsm insulation, adjusts at the hem to seal in warmth, and has two zippered hand pockets. Compared to other midlayers we’ve worn, we’d say the warmth here is less than 80 gsm synth jackets like the Arc’teryx Proton, but warmer than grid fleeces like the Patagonia R1 or REI Flash Hyperstretch. In practice, that’s a great middle-ground.

We’ve used the Nano Puff extensively for summertime forays on its own, and during shoulder season and winter exploits when worn beneath a shell. Going with the hoodless jacket version means you’re saving space in your bag for jackets with them, and like the REI Flash Hyperstretch, the Nano Puff is also a bit more casual-conscious. We think this jacket looks great styled up for a cool night out on the town, or covered in patches — whatever floats your boat.

The Nano Puff can’t be talked about without mentioning Patagonia’s other primo synthetic midlayer, the Nano Air, which is rightfully popular as well. We think the Nano Air works better as a stretchy midlayer with a bit more warmth, but doesn’t look as chic as the Nano Puff. If you’re splitting time between the wilds and the sidewalks, we think this is the better layer.

Other Midlayers We Wear & Enjoy

The awarded midlayers we’ve highlighted above are the ones that bulk out our closets, but there are many others out there that also make the grade. Below are a few additional fleeces and synthetic jackets that we’ve extensively tested and can recommend as solid alternatives.

Rating Details

Warmth 6/10
Breathability 9/10
Durability 6/10
Style 6/10

Specifications

Style
Synthetic hoody
Material
100% polyester brushed mesh
Weight
6.4 oz.
Pockets
One

Pros & Cons

Pros

  • Excellent warmth for its weight
  • Highly breathable
  • Reversible, with each side offering different warmth
  • Comfortable warmth-boosting hood

Cons

  • Average moisture-wicking
  • Relatively delicate
Mary Murphy

The Quick & Dirty: A hybrid midlayer-sunshirt that breathes incredibly well and adds just enough heat to make a difference on high-output adventures.

The super-thin Mountain Hardwear AirMesh Hoody ($120) utilizes Teijin Octa fabric, the same material used in The North Face FUTUREFLEECE. In testing, Bergen Tjossem found that this provides a remarkable warmth-to-weight ratio. At just 4.3 ounces in men’s medium, the shirt feels nearly weightless, yet the brushed interior mimics the loft of a much heavier fleece. It’s a specialized tool recommended for trapping heat while moving moisture at a rate traditional grid fleeces can’t match.

The standout feature of the AirMesh is its extreme CFM (cubic feet per minute) rating. During high-output testing on steep, wind-exposed ridges, Tjossem found the fabric acts like a sieve. Even a light breeze cuts straight through the fibers, instantly dumping heat. This makes it an exceptional midlayer under a shell, creating a high-loft furnace. As a standalone piece, it offers zero wind protection.

Our field testing highlighted the hoodie’s versatility across temperature swings. On a late-season climb where the thermometer hovered near freezing, the AirMesh stayed comfortable during the uphill grind without the swampy buildup typical of synthetic layers. The active fit stays close to the body to maximize wicking, while the mechanical stretch allows for unrestricted movement during technical scrambles.

Durability is the primary trade-off for such a lightweight knit. The open-weave structure is prone to snagging on rogue branches or abrasive granite. On a testing stint involving thick brush, Tjossem noticed the fibers starting to pull slightly. We suggest treating it as a technical component of a layering system (shielded by a windshirt or rain shell) rather than as a standalone outer layer for bushwhacking.

Ultimately, the AirMesh is for the fast-moving crowd who needs high-loft insulation without overheating. It compresses to the size of a large orange, making it a permanent fixture in packs for everything from summer alpine starts to winter trail runs. If you prioritize breathability and weight over wind resistance, this is a top-tier replacement for an old-school fleece.

Rating Details

Warmth 7/10
Breathability 7/10
Durability 7/10
Style 6/10

Specifications

Style
Puffy jacket
Material
12-denier recycled nylon exterior, 10-denier nylon interior
Insulation
60 g/m² PrimaLoft Gold core; 40 g/m² PrimaLoft Gold hood and sleeves
Measured Weight
12 oz. (men's medium)
Pockets
Three

Pros & Cons

Pros

  • Trim fit for layering over top
  • Breathable PrimaLoft Gold and face fabric breathes well
  • DWR finish on exterior holds off precipitation well

Cons

  • Short hem line and trim fit overall
  • Face fabric isn't the most durable at 12-denier
Mary Murphy

The Quick & Dirty: A body-mapped active insulator that targets the sweet spot between a breathable fleece and a traditional puffy.

The Montane Fortes Lite Insulated Hoodie ($290) is built for the stop-and-go reality of mountain travel. At the heart of the jacket is PrimaLoft Active Vent insulation, which breathes exceptionally well when the heart rate climbs. During field testing on steep, late-season approaches in the North Cascades, the 10 CFM air-permeable lining stood out. It effectively moved moisture vapor away from the body, preventing the chill that usually hits the moment you stop to transition.

Technically, the Fortes Lite is a climber’s midlayer. It hosts what Montane calls REACH articulation and a PIVOT 2 hood, which we put to the test on vertical granite scrambles. The hem stayed tucked firmly under a harness even during high-reaching moves, and the hood stayed put without obstructing peripheral vision. The 12-denier face fabric is impressively quiet and supple, though its thin denier prioritizes weight savings over the bombproof ruggedness of a heavier midlayer.

At 11.2 ounces, the warmth-to-weight ratio is dialed for movement. Montane body-mapped the fill, placing 60g Primaloft Gold in the core and 40g in the sleeves to dump heat at the extremities while protecting your vitals. The self-sealing cuffs also integrate seamlessly with gloves. A two-way front zipper makes accessing a belay loop a non-issue.

This isn’t a static puffy meant for sub-zero belay stands, as the high-airflow design means wind will cut through it. However, for mountaineers and fastpackers who need a single piece to replace a traditional fleece and windshell, the Fortes Lite is a top-tier contender. It manages the internal microclimate better than almost any traditional grid fleece we’ve tested this year.

Rating Details

Warmth 6/10
Breathability 9/10
Durability 6/10
Style 7/10

Specifications

Style
Fleece
Material
Polartec Alpha Direct 90
Insulation
N/A, grid fleece
Weight
5 oz. (Men's Medium)
Pockets
N/A

Pros & Cons

Pros

  • Extremely breathable fleece
  • Super lightweight and perfect for active use or sleeping in
  • Snug hood
  • Cozy feel

Cons

  • Can be fragile
  • Difficult to get your hands on with sporadic drops of stock
Mary Murphy

The Quick & Dirty: A minimalist Polartec Alpha Direct layer offering an unmatched warmth-to-weight ratio. The gold standard for thru-hikers, though its open-knit structure requires a wind shell to maintain static warmth.

Now the standard uniform of thru-hikers across the country, the Senchi A90 Half-Zip Hoodie ($115) is an ultralight fleece that excels as a wear-it-all-day piece. Made from Polartec Alpha Direct 90, the A90 weighs between 4 and 6 ounces and breathes so well that we can keep it on while hiking at a decent clip.

A simple half-zip hooded design keeps the A90 low-bulk and easy to layer over. The Alpha Direct fabric is incredibly airy and breathable, with the pile fleece facing outward. The chest zipper is just enough to blow off some excess steam when working hard on a climb, and the thumb holes are perfectly placed to cover the hands with the sleeves.

The North Face FUTUREFLEECE is a comparable mainstream fleece with the yarn facing inwards and a harder face material. This makes the piece more durable, but also a bit warmer, making it better for colder weather. For wearing all day in cool conditions or sleeping in, the A90 is the better choice. 

The downside to the Senchi is attempting to get your hands on one. Like the uber-popular Melanzana fleeces, Senchi releases these midlayers in drops due to demand. We’ve also seen some durability issues with the delicate fabric, having ripped the sleeve of one of our earlier versions. Nothing a little needle and thread can’t fix, but it is a concern for those putting serious miles on these fleeces.

If you can snag one, the A90 Half-Zip Hoodie won’t disappoint. It perfectly complements a light down jacket in a backpacker’s loadout, acting as active warmth and adding some sleeping comfort to cold nights. 

Rating Details

Warmth 6/10
Breathability 8/10
Durability 7/10
Style 8/10

Specifications

Style
Synthetic hoody
Material
40D Delta face fabric; 20D Fortius Air 88% nylon, 12% elastane liner
Insulation
40 gsm Coreloft Stretch with Octa fleece side panels
Weight
9.9 oz.
Pockets
Two handwarming pockets

Pros & Cons

Pros

  • Super thin sheet synthetic layer
  • Body-mapped insulation puts warmth and breathability where you need it
  • More wind-resistant than expected
  • PFAS-free DWR finish

Cons

  • Fairly pricey
  • Little static warmth
Mary Murphy

The Quick & Dirty: A minimalist insulation piece featuring Coreloft in the chest and uninsulated fleece side panels. It provides only minimal warmth for true winter conditions, so it’s better for summer alpine starts.

The Arc’teryx Atom SL Hoody ($280) has become one of our top-choice trail running or cycling layers for quick-paced efforts in cold conditions. The lightest member of the Atom line, this hoody dumps excess heat when you’re working up a sweat, and it packs away compactly.

This is just about the thinnest synthetic midlayer you’ll find out there, and it’s only insulated in the torso, meaning it’s more suited to warmer conditions (or when you’re providing your own warmth). The arms and hood are uninsulated, with Octa fleece side panels and underarms to keep moisture moving.

The material tech doesn’t end there, either. Inside the sleeves is a thin mesh lining that helps wick away sweat, and the whole jacket is treated with a PFC-free DWR finish to fend off light precip. Don’t expect much from this (our testing proved as such), but it is helpful if you’re caught out without a shell.

Compared to The North Face FUTUREFLEECE, the Atom SL certainly turns away breezes better and works more like a standalone jacket than the insulation-only fleece. The Outdoor Research Deviator is fairly similar and is a cheaper alternative for similar outdoor uses.

Ultimately, the price keeps the Atom SL from ranking higher in our midlayer lineup, as $280 is pretty steep for a layer that doesn’t provide much warmth on its own. Instead, we think the high-caliber materials make it a grail piece: If you want the nicest thin synthetic layer out there, this is it.

Rating Details

Warmth 6/10
Breathability 8/10
Durability 7/10
Style 7/10

Specifications

Style
Synthetic hoody
Material
30-denier 100% recycled polyester air-permeable shadow stretch ripstop
Insulation
FullRange
Weight
8.6 oz.
Pockets
One

Pros & Cons

Pros

  • Supremely comfortable
  • Breathes as well as fleece
  • Stuffs into its chest pocket with a carabiner clip-in point
  • Athletic fit great for layering

Cons

  • Not super warm
  • Minimal weather protection
  • Delicate
Mary Murphy

The Quick & Dirty: A hyper-breathable layer that pairs a 40g synthetic fill with an air-permeable face fabric. It’s less durable than standard hardshell-compatible midlayers, however, so consider the durability ding before buying.

The original Nano-Air has been an all-time mega hit for Patagonia. The brand released a more breathable hybrid fleece with Nano Air Ultralight Hybrid, and now the Nano-Air Ultralight Hoody ($249) aims to hit a sweet spot between warmth and breathability. If you’re a fan of the original, have the cash to burn, and love tweaking your layering system to perfection, you’ll love this lightweight jacket.

The big difference between the ultralight and the original Nano Air is that there’s simply less insulation. While the regular Nano-Air packs in 60 grams of breathable Fullrange insulation, the Ultralight version pares it down to 20 grams, has a thin layer of Patagonia’s Capilene material in the forearms, and eschews the hand warmer pockets. The Ultralight is almost half the weight of the original.

This is an excellent layer for ski touring, especially on cold days when the wind is calm. You can climb fast and get warm without needing to take off the jacket or getting too sweaty. You’ll need to throw on a puffy if you stop for long or hang out at the summit; the jacket is not warm enough on its own to stand around in on a good ski day. While there aren’t any handwarmer pockets, the chest pocket is large enough to hold a phone or a few energy bars.

The Nano-Air Ultralight is also a great climbing piece. It has an athletic cut and fits well under a harness, with plenty of stretch for a full range of movement. It easily stuffs into its chest pocket and can be clipped to your harness. At 60 degrees in the shade, sport climbing felt near perfect with the Nano-Air Ultralight on.

Our tester has a knack for destroying clothing, and the Nano-Air Ultralight received a small tear on the sleeve during his third time climbing in it. It’s tougher than Patagonia’s Micropuff Hoody (which lasted 3 pitches before it was in tatters). This is something to consider if you are particularly rough on your gear. The Arc’teryx Proton is a similar breathable midlayer, and while it’s not as breathable as the Nano-Air, its a whole lot tougher and quite a bit warmer.

Rating Details

Specifications

Style
Grid fleece hoody
Material
20D stretch woven nylon shell, VerticalX Octa insulation
Insulation
N/A, grid fleece
Weight
12.5 oz.
Pockets
Three

Pros & Cons

Pros

  • High-cardio coverage
  • Versatile temperature range
  • Extended off-season use
  • Enhanced durability in softshell covered areas

Cons

  • Learning curve for layering underneath
  • Drafty in tailwinds
Mary Murphy

The Quick & Dirty: A hybrid hoodie that places insulation where you need it and breathable fleece where you don’t. It excels at maintaining temperature during winter aerobic grinds, but the uninsulated back can be drafty.

Another quick-paced option, the Outdoor Research Deviator Hoodie ($255), landed just behind FUTUREFLEECE and Atom SL in our testing and was made to run in. Using a very similar Octa fleece, the Deviator bucks tradition and leans into a body-mapped style to add wind-blocking panels where you need them.

These stretch-woven softshell panels cover the Deviator’s front, shoulders, sleeves, and hood and protect the areas where you’re likely to feel a headwind. Unlike the FUTUREFLEECE, which you’ll need to pop a softshell over to really trap warmth, this hoodie holds heat where you want it and sheds it where you don’t.

While testing on trail runs around Denver last winter, we found the breathability on this jacket to be unreal: “Perhaps the greatest testament to this jacket’s thermal performance was that it kept me dry while running up a half-mile incline that averages 15% gradient,” M.T. Elliott says. “I got sweaty, sure, but I didn’t feel wet when I jogged farther out onto the windy plateau and managed to dry off without feeling cold.”

Tailwinds, it turns out, are the arch nemesis of the Deviator, and can surprise you when running in this hoodie and changing direction. While we’d typically toss a windbreaker on to negate this, we also found that doubling up the fabric over those softshell panels can lead to some sweat accumulation. All this is to say that the Deviator is much better as a solo act, and it’s for this reason we tend to recommend the FUTUREFLEECE more often.

In its lane, however, it’s tough to argue with the Deviator, and for chilly winter runs, it’s an excellent option.

Midlayer Comparison Chart

MidlayerPriceMaterialMeasured WeightWho It’s For
Patagonia R1 Thermal$2196.5 oz. 91% recycled polyester/9% spandex flat-faced Technostretch fleece15.3 oz.Almost anyone needing a durable, wind-resistant layer for cold temperatures
REI Co-op Flash Hyperstretch $10054% recycled polyester/35% nylon/11% spandex11 oz.Budget-conscious hikers seeking a soft, stretchy, and reliable fleece for under $100
The North Face FUTUREFLEECE$190124 gsm Octayarn — 55% polyester, 45% recycled polyester6.2 oz.Winter runners and ski tourers who need a layer that dumps heat instantly
Arc’teryx Proton Hoody$350Fortius Air 20 face fabric; 20D Toray liner14.6 oz.Multi-sport adventurers who want a breathable puffy that works equally well as a midlayer or a standalone jacket
Patagonia R1 Air Hoody$189100% recycled polyester fleece12.9 oz.Skiers who want a highly breathable knit that manages moisture better than a standard grid
Ridge Merino Cloudripper Grid Fleece$20069% merino wool, 15% recycled polyester, 13% nylon, 3% spandex (body)1 lb., 1 oz.Gear traditionalists who prefer the natural odor resistance and non-plastic feel of a merino-blend fleece
Patagonia Nano Puff$229100% recycled polyester with DWR11.9 oz.Commuters and weekenders who want a classic, windproof town-to-trail puffy
Mountain Hardwear AirMesh Hoody$120100% polyester brushed mesh6.4 oz.Fast-paced adventurers who need minimal added warmth and maximum breathabiity
Senchi A90 Half-Zip Hoodie$115Polartec Alpha Direct 905 oz.Thru-hikers and ultralight enthusiasts who prioritize the absolute highest warmth-to-weight ratio
Arc’teryx Atom SL Hoody$28040D Delta face fabric; 20D Fortius Air 88% nylon, 12% elastane liner9.9 oz.Summer hikers and climbers needing a minimalist insulation piece for chilly alpine starts
Patagonia Nano-Air Ultralight$24930-denier 100% recycled polyester air-permeable shadow stretch ripstop8.6 oz.High-exertion climbers and skiers looking for a puffy that stays on during the uphill
Outdoor Research Deviator Hoodie$25520D stretch woven nylon shell, VerticalX Octa insulation12.5 oz.Aerobic athletes who need hybrid mapping to protect their core while venting heavily elsewhere
Ibex Wool Aire Vest on hiker
Rain or shine, we got out in it all to test these midlayers on their warmth, versatility, and durability; (photo/Rebecca Ross)

How We Tested the Best Midlayers

Our Expert Testers

After testing hundreds of puffies, fleeces, and vests, the GearJunkie staff knows a thing or two about layering. To create this guide, we dug through our dusty closets, scoured the web, and chatted with pros to find the most reliable, stalwart jackets out there.

Our current midlayer testing is led by Senior Editor Nick Belcaster, who resides between the mountains and the sea in western Washington. His range extends from thru-hiking to splitboard mountaineering, and everything requires a specific layering system to nail the effort. He’s tested midlayers across entire seasons to ensure these options are as versatile as they claim to be.

Editor Mary Murphy tested our initial slate of midlayers in late 2021 after wearing scores of layers and settling on a worthy 15. Her gear-testing cred runs deep, and she has tested a wide range of equipment for GearJunkie, including everything from camping stoves to hiking socks.

gearjunkie editor nick belcaster testing the north face papsura midlayer while walking on a glacier in patagonia
Testing the wind resistance of midlayers in Patagonia; (photo/Erika Courtney)

Our Testing Process and Rating System

Midlayers are the workhorses of a layering system, and our testing reflects that versatility. We pushed these garments through high-output aerobic sessions and static high-alpine transitions to find their breaking points. Testing grounds included the cross-country trails of the Methow Valley, ice climbing in the deep-freeze basins of Colorado, and long-distance trekking across Iceland.

Our protocol requires each midlayer to be evaluated across at least three different mountain sports and over at least two seasons. This ensures we understand how a piece performs during a shoulder-season scramble versus a mid-winter skin track. To account for metabolic differences and fit variability, we cycle each top through a pool of testers with diverse body types and temperature tolerances, ensuring our findings aren’t limited to a single perspective.

  • The Breathability Test: To quantify breathability, we perform a controlled high-output climb wearing the midlayer over a standard merino base. Once at the summit, we monitor the time it takes to return to a dry state while stationary. Layers that trap moisture for more than 15 minutes receive lower scores in our Breathability metric.
  • The Overhead Reach & Hem-Lift Protocol: A midlayer that pulls out of a harness or is exposed to chills is a liability. We subject every garment to a reach test, involving full overhead extensions while wearing a pack. We measure the vertical displacement of the hem, and any jacket that lifts more than two inches is docked points in the Ergonomics category, as it fails to maintain a consistent thermal seal.
  • The Loft Compression Recovery Cycle: To test long-term durability and insulation resilience, we subject synthetic and down midlayers to multiple compression cycles into their own stuff sacks (or a standard 1-liter dry bag). Following the final cycle, we measure the time it takes for the insulation to return to its original loft height. This helps us identify which active insulations are prone to packing out and losing their thermal value over a single season of heavy use.
gearjunkie senior editor nick belcaster wearing the black diamond first light hybrid hoodie in the north cascades
Testing the breathability requires building up some steam, then monitoring how long it takes to dry off after; (photo/Erika Courtney)

Our Midlayer Rating System

We rank midlayers using a 100-point scale across four specific metrics, prioritizing technical performance over aesthetics.

  • Thermal Efficiency (Warmth): 25% weighted. Warmth is the primary reason for a midlayer, but we evaluate it through two lenses: static loft and active retention. We measure how well a piece traps heat when stationary at a belay versus how it maintains a comfortable microclimate during exertion. We use a multi-tester consensus to determine if a jacket’s warmth-to-weight ratio justifies its place in a pack.
  • Breathability & Vapor Transfer: 25% weighted. In an active layer, breathability is the necessary counterweight to warmth. We monitor how quickly perspiration builds up during steep climbs and, more importantly, how fast that moisture dissipates once the intensity drops. We favor pieces that balance high-CFM (airflow) fabrics with insulation that doesn’t wet out from internal moisture.
  • Long-Term Durability: 25% weighted. A midlayer should survive more than one season. We look for signs of mechanical failure, such as insulation packing out, fabric pilling under pack straps, or zippers snagging. We specifically assess the denier of the face fabric and the resilience of the baffles or fleece grid after repeated compression cycles and washings.
  • Ergonomics & Style: 25% weighted. While technical specs come first, a layer’s utility is tied to its fit. We assess the livability of each piece, and look for harness-compatible pockets, helmet-friendly hoods, and a cut that allows for full range of motion. Finally, we consider the trailhead-to-town factor: how well the garment’s aesthetic translates to everyday wear once the mission is over.
gearjunkie tester chris carter wearing the patagonia nano puff while hiking the cumberland trail and testing for breathability
Backpacking along the Cumberland Trail with the Patagonia Nano Puff; (photo/Emily Malone)

Buyer’s Guide: How to Choose a Midlayer

Which Midlayer Is Best: Jacket or Vest?

The first thing you should decide when browsing for a midlayer is whether you want a full jacket, hooded jacket, or an insulated vest. Some midlayers are a hybrid of both — insulated in the core, with just a face fabric for the arms (like merino).

Some are also water-repellent, and some aren’t. Our advice is to look at the big differentiators up top, and then look later at specific features.

Midlayer Insulation

There are a few types of insulation used in midlayers, but the most common ones we’ve seen are the man-made technologies used in synthetic insulated jackets. Brands like PrimaLoft make different types of synthetic insulation, from high-warmth blends to eco/recycled ones. Some brands will also have in-house insulation technologies.

Jackets will have different amounts of insulation, too — we’ve found the sweet spot is to look for a midlayer with 60-100 grams per square meter (GSM) synthetic insulation. Many midlayers also don’t use added insulation — instead, they use a heavier fabric, like fleece jackets.

If you aren’t buying an insulated layer, pay attention to the warmth level of the fabrics used. For example, a midlayer hoodie with merino construction or a merino liner can still provide lots of warmth and versatility, even if it isn’t stuffed with insulation.

a gearjunkie tester wearing the north face futurefleece while ski touring in colorado
Testing the FUTUREFLEECE while ski touring in Colorado; (photo/Jessica Gresho)

Price & Value

Since midlayers can be made from a variety of insulations, they tend to range broadly in their prices. Also, consider that many are tailored to excel at different paces or temperature ranges and that simply going with the warmest layer you can afford might lead to overheating. Dial in on the sport-specific layering system you’re looking to perfect, and consider what aspects you need most from your midlayer.

Budget

The budget range of midlayers is typically grid fleeces, which will run you around $100. These layers won’t pile on the features or fine trim but instead focus on providing reliable warmth when you need it. Fleece is reliable warmth once you build up some heat under it, and while it won’t hold back from strong winds, a light windbreaker will protect you.

The $100 REI Co-op Flash Hyperstretch Fleece Jacket has a lot in common with our top pick and even a few features that it lacks, including a drawstring hem and a touch more stretch. Most fleeces in this price range will use in-house pile fleeces to keep costs down and may skip out on niceties such as thumb holes in the sleeves.

Mid-Tier

Bumping up a bit in price also means more warmth, and this range is where you’ll be able to get into synthetic puffies like the Patagonia Nano Puff ($239). These midlayers can be warmer than fleeces and boast more features, such as hand-warming pockets, adjustable hoods, and different weights of insulation to adjust warmth and breathability.

Higher-end fleece technologies can also be used in midlayers in this range, with Polartec and Octayarn being notable. The $170 The North Face FUTUREFLEECE uses a techy eight-sided hollow yarn to weave its fleece and build in even more trapped air space, while the Arc’teryx Atom SL Hoody ($280) adds on a layer of 40g insulation for even more warmth.

Premium

High-end midlayers will often run you north of $300, but will be trimmed out in the nicest materials that are sure to pay dividends in durability. Look for name brands like Pertex fabrics and PrimaLoft synthetic materials to ensure you’re getting what you pay for.

The merino wool insulation used in the Ibex Wool Aire Hoodie ($285) assuredly explains the price of this jacket, but we argue it’s well worth it. The $350 Arc’teryx Proton Hoody was the most expensive midlayer we’ve recommended, but now, after 5 years of hard use, it’s still nearly as warm as it was on day one. You’ll pay up front, but the longevity can be worth the spend.

a selection of midlayers hung in a tree
A handful of midlayers we tested throughout the fall; (photo/Mary Murphy)

Frequently Asked Questions

What makes a good midlayer?

A quality midlayer drives your layering system by trapping body heat and managing moisture. Effective insulation relies on materials like merino wool or synthetic grid fleeces, which retain warmth even when damp. Fabric density is also a key performance indicator: look for midweight or heavyweight knits between 200 and 270 GSM to provide thermal protection without excessive bulk, ensuring the piece withstands cold temperatures while remaining highly packable.

To handle high-output movement, a midlayer must prioritize breathability and durability. Features like quarter-zip vents allow for quick temperature regulation, while core-spun fabrics (natural fibers wrapped around a nylon core) provide the abrasion resistance needed to endure backpack friction. The fit should remain close to the body to maximize thermal efficiency while incorporating enough stretch for a full range of motion.

What’s the warmest midlayer?

The warmest active midlayers host high insulation density and superior thermal efficiency, moving beyond standard fleece to advanced synthetic insulation that traps heat. For high-output mountain pursuits in extreme cold, look for specialized technical jackets utilizing lightweight, stretch-infused face fabrics paired with resilient lofted insulation. These advanced layers create a thick buffer of dead air, yet allow moisture and excess warmth to escape when you are moving quickly.

Excellent examples of this design include the Arc’teryx Proton Hoody, which features 80g/m² PrimaLoft Gold Active insulation, and the Himali Ascent Stretch Hoodie, which relies on a dense 100g PrimaLoft Gold Active+ fill. Both midlayers maximize warmth by pairing high-performance synthetic insulation with a slim, athletic cut that fits perfectly beneath an outer shell.

How do I layer a midlayer with a shell and base layer without losing mobility?

Achieving optimal warmth without restriction requires matching the fit and fabric surfaces of your entire kit. While your base layer should be skin-tight, your midlayer needs an athletic fit, but be spacious enough to sit over your base layer. Avoid pairing high-friction fleece with an unlined shell, which causes fabrics to catch and bind.

Furthermore, look for construction details like gusseted underarms, articulated elbows, and four-way stretch materials that mirror your body’s mechanics. When testing your system, lift your arms overhead, as an integrated setup lets you reach comfortably without the midlayer binding across your back. Finally, ensure your shell is roomy enough to accommodate your midlayer’s loft. Compressing your insulation under a tight shell squishes the dead air space needed to trap heat, neutralizing its warmth.