Arc’teryx’s Delta Jacket is a lightweight fleece made from Octa Fleece, one of the newest high-tech fleeces to hit the market in the last few years. The name comes from the octopus-like weave that creates air holes, which help trap heat while also allowing moisture to pass through. It’s very popular with cottage industry ultralight brands, but Arc’teryx adopted it for the 2025 revision of the company’s popular Delta jacket.
I hesitated to include this jacket in this guide because, while I love it as a light mid-layer for summer trips, there is an older, heavier version of the Delta jacket. Judging by the rave reviews on the Arc’teryx website, it was very popular. This jacket is something else entirely, but disgruntled fans of the older version aside, this is a great mid-layer for summer trips, especially when paired with a sun shirt hoodie. At 8.5 oz for this, and 6 oz for a sun hat like the one from Kuiu below, you have a combination that allows for many layering options and still weighs less than many of the more popular leather grid options. My only problem is that style was, um, not considered in the design of this jacket. One user’s review on the Arc’teryx website compares it to the Mr. Roger, that’s right. But hey, it’s light, it’s functional—who cares about fashion in the backcountry?
