Patagonia Nano-Air Ultralight Review: Breathable Warmth for High-Output Adventures

Patagonia stripped down its Nano-Air jacket to create an ultralight shell for high-output activities while still providing a touch of warmth. I find it to be an impressive layer when I need something to block the chill.

I own nearly all of Patagonia's lightweight insulated jackets at this point, including the Nano-Air, Nano Puff, Micro Puff, Down Sweater, and R1 Thermal. I've included a table farther down with links to our reviews. The Nano Air in particular is the jacket I reach for when I need warmth in dry, cold conditions. It's great for ski touring in the mid-20s to mid-30s (Fahrenheit), but I'll overheat if I try to run in it. Enter the Patagonia Nano-Air Ultralight Full-Zip Jacket, a minimalist shell with some active insulation. At just 8.8 ounces, it joins a class of ultralight jackets that still provide warmth.

First Impressions of the Patagonia Nano-Air Ultralight

The Patagonia Nano-Air Ultralight is great when you need to cut the chill while being really active. Its minimalist design fits the use quite well; the slim cut and lack of handwarmer pockets makes for a great fit. The Nano-Air Ultralight doesn't flap around when I run, and I find myself wearing this jacket as a windbreaker around town when temps are in the 40s, as long as I won't be out for too long. I get noticeably cold under my arms when standing around in a chill breeze due to the Ultralight's (very) breathable panels. While this breathability is great while hiking and running, it highlights the Ultralight's focused on high-output activities and its resulting lack of versatility compared with slightly heavier jackets. 

The Patagonia Nano-Air and Nano Puff, for example, aren't any use for something as active as running, but they excel as both mid-layers and everyday, lightweight jackets. The Patagonia Nano-Air Ultralight is not your do-it-all layer, but it's an impressive jacket that provides just the right amount of warmth for high-output pursuits in cool weather. I'm not usually interested in half-zip jackets, but its Nano-Air Ultralight Pullover sibling is definitely worth considering if you're a fan of that style.

Materials & Construction 

Patagonia has paid attention to every detail with the Nano-Air Ultralight. The shell is made from 1.6-ounce, 30-denier 100% recycled polyester air-permeable shadow stretch ripstop, the same fabric found on the Nano-Air. Because this jacket is insulated (more on that below), there are two layers of this polyester. Insulation has been eliminated under the arms, resulting in a single layer of this very light 1.6-oz shadow stretch polyester. There is a stretch panel on the forearms of this jacket which use a 2.3-oz 100% recycled polyester double knit with a wicking finish. These panels have a brushed feel and and even more stretch. 

Pockets

This stripped down jacket has a single chest pocket. Handwarmer pockets have been eliminated in an effort to shave weight and, more importantly, bulk. The Nano-Air Ultralight stuffs into the chest pocket, which features a double-sided zipper pull. When stuffed, the Ultralight is impressively small. Even the Micro Puff looks bulky in comparison. This jacket is easy to stash in your running vest or day pack. 

Zippers

The Nano-Air Ultralight features a YKK #3 hidden coil main zipper. It runs smooth and makes more sense for an ultralight jacket compared to the molded-tooth zipper found on the Nano-Air. Patagonia is usually really thoughtful about the hardware they use on their jackets, and this is no exception. So far I have zero complaints about this zipper.

Warmth and Insulation

Bottom line on warmth: In my testing I find this jacket to be great for hiking anywhere from 60°F to 40°F depending on windchill and how hard I'm pushing myself. For running I give it a comfort range of 50°F to 30°F. I don't wear more than a t-shirt on a run at 50°, but it is great for a light jog at that temp when the wind is chilly. With an added longsleeve compression baselayer this is a great layer for ski touring down into the 20's as long as I'm going uphill, otherwise too much air comes in under the arms . That's when I reach for the Nano Air.

The Patagonia Nano Air Ultralight uses 20-g FullRange® 100% recycled polyester, which is proprietary to the brand. The rating of 20 grams is the insulation's weight per square meter. This is on the absolute light end for any synthetic insulation used in a jacket. Even comparable jackets like the Arc'teryx Atom SL use a 40g insulation. The Nano Air Ultralight is one of the lightest and most breathable insulated jackets on the market. It is also the lowest in terms of warmth relative to lightweight jackets.

Weather Resistance

Bottom line on weather resistance: The Patagonia Nano Air Ultralight is going shed light rain and snow for short periods of time. It is great to bring along for any unexpected weather on a cool day, but I wouldn't want to be out for long.  That said, this feels very appropriate for the intent of this jacket as providing a hint of warmth for high-output activities in cool weather. This is a great jacket for staving off a short rain on a long hike.

The Nano Air Ultralight has a PFAS-free DWR coating. Patagonia was an early leader in the effort to remove "forever chemicals" from their products. They have also been transparent about the performance shortfalls of PFAS-free coatings in terms of water repellency. Thankfully, we're seeing performance improvements every year as brands race to meet regulations that ban PFAS in outdoor apparel (California and New York banned PFAS starting January 1, 2025, while Colorado has a ban starting January 1, 2028). For 2025, 100% of new products from Patagonia are made without any intentionally added PFAS (that's legal speak for PFAS-free). Check out this page from Patagonia with great info on their PFAS-free technology.

In practice the DWR on the Nano Air Ultralight is going to keep water beaded on the surface of the jacket for a short period of time  but at some point it will wet out. The FullRange insulation will continue to work when wet, but expect to get chilly with wet liner fabric that sticks to you. It's worth noting that the forearm panels take on water immediately.

Fit & Feel

I love the fit of the Patagonia Nano-Air Ultralight. The jacket moves with you and never feels like it's flapping in the wind. This is the lightest insulated jacket I've ever worn - if it were any lighter it would be a tech tee. I used to run on cool days with the Patagonia R2 TechFace, but the Ultralight is lighter and more breathable.

Here is what I like about the fit:

• Slim fit - Not only is it trim through the torso, but the arms are slimmer than any other Patagonia jacket I've worn.
• No handwarmer pockets - This really helps eliminate weight and bulk. 
• No adjustment on the hem - Hem adjustment isn't needed with the slim fit, so getting rid of the drawcord and barrel is another place where this jackets saves grams. It also means less bounce when moving.

One thing that could be done better:

• Hood -  Patagonia calls this their Light Touch Expansion Hood, and it can fit over a climbing helmet. It still fits well around the face because they've added a seam just below the ear with the smallest amount of passive cinching. This keeps the hood out of my face, because I don't wear it with a helmet. I get why they have the expandable hood, but I'd like it even better if Patagonia made it smaller. The helmet-compatible size results in more material under your chin. If I have one complaint about the fit of this jacket, it's that there is too much material when I zip it up with the hood down.

The Patagonia Nano-Air Ultralight Pullover

It's very rare for me to consider a half-zip version, but the Pullover variety deserves consideration. It features a two-way main zip. The jacket is so light and breathable that you give up much with the pullover. It's going to fit even better without the full zipper. And without the hood, the fit at the chin is much improved. The pullover also is a great midlayer when you need something more than a shirt under your rain shell.