MID LAYERS

A mid layer sits between a skin-hugging base layer and a waterproof outer layer. Here’s our guide to the best options you can buy for going out on the trails.

1 FLEECES

For versatile all-round performance, fleece is still the most popular mid layer. Warm, comfortable and breathable, polyester fleece comes in multiple variations; from lightweight, breathable gridded microfleece tops to uber-cosy, high-loft fleece hoodies. Its main drawback is environmental: polyester is a synthetic fabric made from petrochemicals, which is not great for the planet. Many fleeces are now made from recycled polyester, which partly addresses this issue. But disturbing research has also shown that fleece’s fluffy fibres can also release tiny strands and particles – called microplastics – into the environment, especially during the washing process. The outdoor industry is trying to find solutions to this serious issue.

INSULATED JACKETS 2

If you’re looking for optimum warmth for weight, a synthetic or down insulated ‘puffer’ jacket is the obvious choice. They’re often too warm for active use, though hybrid insulated mid layers, incorporating more breathable fleece panels, help to overcome this limitation. Choosing between down or synthetic fill can be tricky. Down jackets are lightweight, packable and very warm, while synthetic jackets are usually cheaper and more resistant to moisture. If you plan to use your insulated jacket as an extra throwon layer for rest stops and chilly wild camps, go for one with a hood. If you’ll primarily be using it as a mid layer, then a hood might not be so essential.

SOFT SHELLS 3

Soft shell jackets are versatile layers that are more windproof and protective than a fleece and more comfortable and breathable than a waterproof hard shell. They can be used as mid layers or outer layers, though they aren’t a substitute for a waterproof jacket in heavy rain. Soft shells come in many different variants – some are light, stretchy and breathable, others are heavier, warmer and more protective. They’ll typically have more technical features than most fleeces or puffers, with multiple pockets, adjustable cuffs and hem, and a fully adjustable hood.

ACTIVE INSULATION 4

The latest breed of insulated mid layers are ‘active insulation’ pieces, designed to provide superior warmth to weight compared to fleece, while still being breathable enough to wear all day, unlike conventional down or synthetic puffers. These usually consist of a tightly-woven nylon or polyester face fabric combined with a fluffy, openweave insulation as an inner lining.