Best High-Loft Fleece Jackets for Extreme Cold Weather Layering

High-loft fleece is a deep, fluffy polyester knit that traps lots of still air—exactly what you want from an insulating midlayer under a wind or waterproof shell on frigid days. It delivers exceptional cozy, static warmth, but it’s bulkier and less breathable than technical grid or hybrid fleece, which trade loft for airflow and quicker dry times for active use. In short: choose high-pile for camp and low-output cold, and grid/hybrid fleece for high-output winter hikes and ski tours. Independent roundups consistently confirm these trade-offs—warmth and comfort versus breathability and packability—across fleece types and models from casual to performance builds, with recurring notes on pilling under pack straps and the importance of a shell for wind protection (see testing syntheses from Treeline Review).