Midlayers are designed to provide insulation during activity while managing moisture, excess heat and changing weather. In testing across hiking, skiing, fat-biking and climbing, six insulated jackets stood out for their balance of warmth, breathability and practicality.
The Arc’teryx Atom Hoody was selected as the best overall model. Its synthetic insulation, fleece side and underarm panels, helmet-compatible hood and multiple pockets give it a versatile combination of warmth and ventilation. Testers found it warm enough for winter activities in the teens without an outer layer, while its fluorocarbon-free DWR finish helped repel light drizzle. However, the jacket can be too warm for mild conditions and showed some pilling after repeated contact with pack straps.
The Ortovox Ravine Metawool 90 uses a wool and synthetic insulation blend that remains warm when damp and resists body odor. Its recycled materials and wool sourced from sheep in the German Alps also give it a strong sustainability profile. The roomy cut accommodates layers and works well beneath a freeride-style shell, although the jacket is relatively bulky when packed and its small zipper pull can be difficult to operate.
Mountain Hardwear’s Kor Alloy Jacket was identified as the most durable option. Its nylon ripstop shell, Pertex Quantum Air fabrics and reinforced construction offered strong resistance to abrasion and tearing without sacrificing breathability. The jacket includes four front pockets and performed well for resort skiing, backcountry travel and climbing. It is less insulating than some of the other options and is best suited to temperatures above 20 degrees.
The Stio Dawner focuses on breathability for high-output activities. Its stretch nylon shell, fleece-like Octaknit interior and athletic design helped testers manage sweat during cross-country skiing, running, fat-biking and other demanding efforts. It compresses to roughly the size of a grapefruit and includes a helmet-compatible hood, but provides limited warmth in temperatures below 15 degrees or during low-intensity activity.
The Black Diamond First Light 1.0 Stretch Hoody uses strategically placed synthetic insulation and breathable Merino wool panels on the back and underarms. This construction helps limit overheating when worn with a pack, while its stretch fabric supports unrestricted movement. The jacket packs into its chest pocket, though sizing ends at XL and the close fit may not suit every wearer.
For very cold conditions, the Marmot WarmCube Active Novus Hoody combines substantial synthetic insulation with open channels intended to improve mobility and ventilation. Testers used it in temperatures ranging from 10 degrees below zero to 15 degrees and found it warm without feeling excessively bulky. The open construction also allows wind through, so a shell is recommended in wet or gusty weather. Its fit is notably roomy, and some users may prefer to size down.
Choosing a midlayer depends primarily on the balance between warmth and breathability required by the activity. Fleece-backed designs generally offer the greatest ventilation, while synthetic-insulated jackets provide more warmth and remain effective when damp. Hybrid constructions can offer a useful compromise for cold-weather exertion.
For fast-paced activities, a breathable layer can help prevent sweat buildup, while colder or windier conditions may call for a jacket with more synthetic insulation. Wool also retains warmth when wet, although it absorbs water and can become heavier over time. In severe cold or during slower activity, a thicker option such as the Marmot WarmCube Active Novus may be appropriate; for changing conditions, carrying two lighter layers can provide more flexibility.
A waterproof shell can supply most of the protection from heavy precipitation and wind, allowing the midlayer to focus on insulation and moisture management. Without a shell, look for a jacket with some resistance to wind and light rain, such as the Arc’teryx Atom or Ortovox Ravine Metawool 90.
The review notes that synthetic or wool insulation is generally better suited than down to midlayer use because it maintains warmth more reliably when exposed to sweat and light precipitation. Hooded models add warmth and protection, but a hoodless midlayer can be more practical beneath a hooded shell in stormy conditions.
The testing process examined the fit, warmth, breathability, mobility, weather resistance and usefulness of midlayers across activities. Testers also assessed how each jacket worked with backpacks and other layers, selecting only models that performed well in both technical use and everyday wear.
Sources: Outside.