Fleece is a breathable insulating layer that remains comfortable during active use and dries relatively quickly. It works well between a baselayer and shell, or as an outer layer in dry, mild conditions. For beginners, fleece is one of the easiest and most versatile ways to add warmth.

Compare fabric weight, warmth, breathability, wind resistance and bulk. Lightweight grid fleece suits higher-output activities, while thicker fleece provides more warmth at a lower pace. Also consider whether the surface slides easily under a shell and whether pockets remain accessible when layering.

Fleece and insulated jackets do different jobs. Fleece usually breathes better and handles moisture well during movement; down or synthetic insulation usually provides more warmth for its weight when activity slows. Wind passes through many fleece fabrics, so a shell can greatly increase warmth.