My Favorite Chilly Trail Running Layer: Norrøna Senja Warm1 Hood Review

Leave it to a Norwegian company to create a trusty midlayer for aerobic adventures in the elements. Norrøna’s Senja Warm1 Hood is a lightweight, quick-drying workhorse that’s weaseled its way into many of my high-output adventures. When I don’t want to get cold as my sweat evaporates, this breathable and synthetic fleece helps me stay warm and happy.  

Many fleece jackets are geared toward low and moderate-output activities like downhill skiing (read: sitting on a chilly chairlift) or camping (imagine: standing around a fire when the sun goes down). But there’s a real gap in the market for a fleece that allows you to do higher output activities in moderate-to-cold temperatures and unpredictable weather without making you sweat a storm.

That’s where the Norrøna Senja Warm1 Hood jacket comes in. The jacket is incredibly versatile. It can be worn alone as a base layer or as a midlayer. You can also layer on a puffy or shell, depending on the temperatures. The slim-fitting hood is nice if the wind picks up on an exposed ridgeline, and that long front zip helped me dump heat — or rein it back in when my core temp dropped. 

In short: The Norrøna Senja Warm1 Hood jacket ($189) is a barely there fleece midlayer that I used for trail running, mountain biking, hiking, and nordic skiing. The thoughtful design and nifty features kept me warm and ready to keep crushing mile after mile. 

Check out our GearJunkie Fleece Jackets for Women buyer’s guide for more options.

Norrøna Senja Warm1 Hood Review

I love trail running, hiking, and mountain biking in the shoulder seasons of fall and spring. But if you live in the Rockies like me — a former Jackson, Wyo., resident now living in Missoula, Mont. — you know these times of year are unpredictable. I often find myself too cold or too hot, cursing my layering choice while promising myself I’ll do better next time. Easier said than done. 

The first time I wore the Norrøna Senja Warm1 was on a high-alpine hike in Grand Teton National Park. It was September, which means it could be 40 degrees and raining, or 75 degrees and sunny. Over the course of the day, hiking to a mountain lake with 3K feet of vertical gain, the weather was in both camps. 

I threw this lightweight layer over a short-sleeve wool base layer for the first few miles. As I hiked, I warmed up. So, the jacket went in my pack until we reached the second alpine lake at 10K feet. Gusts and clouds made me thankful I had this layer to pull back on while exploring the lakeside, filtering water, and on the descent.  

Throughout the day, I was pleased with its breathability. The attention to details (like the hood, fit, and pockets) take it from basic to technical. So began my love affair with this midlayer that’s continued on trail runs, hikes, and mountain bike rides all around the mountains of Montana. 

Supreme Breathability 

Recycled polyester is what keeps the Senja Warm1 warm yet breathable and quick-drying. The sleeves and front are made with denser textiles. The back and underarms have a lighter, more breathable weave that’s more mesh-like for moisture management, where you’re likely to sweat.

The polyester is 100% recycled. And the materials are Bluesign-approved, signifying that strict safety and environmental requirements were met during the manufacturing.  

If you end up sweating, fear not — the fabric is treated with an anti-stink odor treatment. A solution is applied to the fabric that helps remove the fat and protein from sweat, starving bacteria of the nutrients they need to grow. In return, odors are reduced. I can wear this layer numerous times without washing, even after a particularly sweaty trail run, and it doesn’t smell bad. 

In front, the anorak-style quarter zipper is more like a half-zip and increases this layer’s breathability. You can zip the collar up to the middle of your neck if you’re cold. You can also vent all the way down to your belly button if necessary.

Sun Protection, Hood, Chest Pocket 

Nifty details keep this jacket adaptable to the conditions depending on your adventure. A mix of UPF 30 and UPF 50 fabric is a nice touch for sunny days.

The close-fitting hood is lightweight and streamlined, making it easy to pull on and continue your activity without batting an eye. It fits smoothly over a slim beanie or headband. I also like the single zip chest pocket for essentials like chapstick or headphones while running.  

Packable and Versatile 

A good adventure layer doesn’t take up a lot of space, and the Norrøna Senja Warm1 Hood is no exception. Clocking in at a mere 7.8 ounces for a size medium, this jacket is incredibly packable. 

I bring this layer when I know it might get cold or I might sweat. It’s easy to pull off and on throughout the day. The fleece also easily stuffs into my 5L hip pack on chilly mountain bike rides. There’s still room left over for snacks, a tire kit, and a few tools.

On runs, this layer folds down small enough to fit in my vest’s back pocket. My usual trail runs typically start in a gully or valley bottom before ascending a ridge, where it can be blustery. I love throwing this on to keep my pace up and stay comfortable in more exposed zones. 

The jacket comes in three colors. While neon orange is a somewhat rare color for women’s outdoor clothing, I appreciated its vibrance while running near road traffic in low light.

Critiques

As with many fleeces and base layers, the Norrøna Senja Warm1 Hood isn’t wind-blocking or water-resistant. The few times I wore this piece as a base layer with nothing but a sports bra underneath, I could feel every breeze.

To help, I recommend a tank, short-sleeve, or long-sleeve base layer underneath to block wind depending on the temperatures. On top, I recommend a windbreaker or other outer layer if heavy wind or rain is forecast.

The fit is pretty dialed — athletic, slimmer cut, and true to size. But one element that felt too tight were the thumb loops and sleeve cuffs. They need more stretch! My Garmin watch felt too constricted without pushing the sleeve up to accommodate it. If you can, pair this layer with a slim watch only. And leave bracelets at home if you want to cover the back of your hands with the thumb holes. 

Norrøna Senja Warm1 Hood: Conclusion 

After a year of high-impact outdoor adventures, it’s safe to say the Norrøna Senja Warm1 Hood isn’t going anywhere. It’s my new go-to layer for alpine hiking and running when I want to stay warm, no matter the temperature fluctuations. 

This fleece, which sometimes acts more like a beefy base layer, stands out for its breathability during high-output activities. It’s a great companion for variable conditions — just stuff it in whatever pack you’ve got, knowing that if gusts arrive or you catch a chill, you’ve got a thin, warm layer to grab.

The thumb loops, hood, zippered pocket, and generous anorak-style zip are all great design details. The SPF protection never hurts, especially at high elevations.

Ultimately, the Norrøna Senja Warm1 Hood women’s fleece jacket is a great way to round out your layering systems with one that is quick-drying, lightweight, and super-breathable. I’m excited to keep wearing this fleece on everything from fall mountain bike rides and jogs to summer jaunts in the high alpine.