On Zero Review

Designed and tested with On's running team across the globe, the On Zero is an ultralight jacket that moves with your body fluidly and efficiently; we felt it nearly disappear on the body when we wore it on our runs. This jacket is truly stripped down, and the minimal design eliminates extra details and unnecessary features to achieve an ultralight weight.

Breathability

The On Zero is a stylish jacket that makes you feel fast, and while running fast, you build heat. Thanks to the mesh mapping underarms with underarm featuring 95% Recycled Polyamide, 5% Elastane fabrics and thin materials, this jacket breathes very well. This makes it a perfect option for higher intensity running and interval sessions. We never overheated while wearing the Zero, even with the minimal venting options. We would recommend it as a jacket for those who don't usually like to run in a jacket.

We tested this jacket in a variety of cold and windy environments, on actual runs in the mountains and valleys above Boulder, Colorado. The On Zero has just enough substance without sacrificing breathability, which makes it super practical for running. Even while building warmth in the jacket, there was good airflow.

Weather Resistance

When summiting peaks in Colorado, we experienced some harsh wind events up above the treeline, and this jacket provided great wind protection for its weight. It uses a 100% polyamide material to achieve its light and windproof properties. If you are a fairweather trail runner who often wanders onto some windy ridgelines, it's a good choice.

However, waterproofing is not the Zero's strong point. It performed well enough to get us through brief rain events, but it wets out pretty quickly in anything more than a sprinkle.

Comfort and Mobility

The On Zero was very comfortable and sleek. You definitely notice the premium feel upon wearing, and it is light and airy enough that you never feel restricted in your movements. Most of the jacket is made from a lightweight polyamide material, but the underarm area includes a 5% blend of elastane to accomodate body movement. It is easily one of the most comfortable jackets from our selection.

The fit of the jacket is slim and dialed where it needs to be, and roomy where it counts, never restrictive. On wild and crazy downhills where we had our arms out wide, swinging to keep our balance, this jacket adapted to our every move and added to the flow of the run.

Portability

At 2.2oz, the One Zero is the lightest and most packable jacket from our selection. This is the standout feature that really made us fall in love. Part of the joy of running is moving light and untethered. This jacket really lets you focus on your running and forget about your gear. When a piece of running apparel works, you can forget about it.

Less than the size of a lemon when packed, the On Zero stuffs into an underarm mesh pocket. Yet it remains easily deployable; feel a slight chill and you can get the jacket on in seconds. If you start to overheat or the day is warming up, stash the jacket and tuck it away in your pocket or running vest. The minimal weight and nonexistent bulk practically disappear into your pack, making it a no-brainer item to bring with you on your next alpine run, even if you expect good weather.

Features and Visibility

The On Zero is pretty light on features, which is part of what helps keep the weight down. There is no pocket beyond the stuff pouch, and there is no hood. However, reflective material is scattered near the seams, and there is reflective On branding on the chest to promote visibility in urban and high-traffic areas.

Above all, this jacket works so well in general, so we weren't annoyed by the lack of features. Most of the running jackets we tested are pretty minimal anyway, so the Zero balanced out to just above average in this metric.

Should You Buy the One Zero?

If you get excited by counting grams and finding the lightest gear on the market, this is the jacket for you. It is a good choice if you're heading into the high alpine and have very limited packing space. It also works well if you often experience cold and windy starts, but quickly warm up on your runs. It's breathable enough to wear during the summer months, but we're looking forward to using this jacket for future fall seasons as temps get even cooler and breezier, so we can wear it more often.

What Other Running Jackets Should You Consider?

If you're looking for other lightweight options, check out the Editors' Choice award Inov8 Raceshell HZ which is a bit more waterproof, or check out the Patagonia Storm Racer, which is the ultimate jacket for running in the rain (if you're that hardcore), though it is not nearly as breathable. If you want something similar to On Zero, but less expensive, check out the Patagonia Houdini.