Jackets and base layers are what people tend to grab first when putting together their hiking wardrobe. But the importance of a mid-layer cannot be overstated. It adds that depth and versatility to your layering system, just like adding Worcestershire sauce adds depth of flavour to a casserole.
Mid-layers vary a lot both in performance and design. They can range from a typical fleece or merino to a lightweight down jacket or thicker softshell. In this guide, you will learn what you need to look for in a mid-layer, plus we've recommended some of the best.
What to look for in a mid layer
Breathability vs weatherproofing: While a good level of wind- and waterproofing is desirable in shell layers which form the outer face of your protection, for mid-layers it’s more important that they are breathable, allowing moisture from your sweat to escape without making you feel clammy or cold.
Quick-drying: Part of a mid layer’s ability to keep you comfortable is how quickly it dries. If it wicks your sweat rapidly but then holds on to it, you’ll soon become uncomfortable. Likewise, if you’re caught in a sudden downpour before you can get your waterproof on. A fast-drying mid-layer is essential.
Warmth: Mid-layers come in a variety of forms, from thin fleece to thicker insulated fabrics. Consider the time of year, the intensity of the activity, and your own tendencies to run hot or cold when deciding how warm you need your mid-layer to be.
Bulk: Because a mid-layer will be worn under a shell it’s important that it’s not too bulky. Warmer, more insulated mid-layers may feel overly restrictive once a snug-fitting shell is pulled on over the top.
Fit & stretch: A snug, close-fitting mid-layer will work better under outer layers but can feel restrictive unless the material has a good level of stretch. This is particularly important for more upper-body-intensive activities such as scrambling and climbing.
Venting with zips: Pull-over mid-layers may only have a short neck zip, while full jackets will undo all the way down allowing more warm air to escape if required.
Gilets: Unless you suffer from particularly cold arms or hands, a sleeveless mid-layer may be the best option. It will keep your body warm without increasing bulk within the arms of your shell layer.
The best mid-layers
Rab Syncrino Light Fleece Pull-On
Essentially a technical zip-necked sweater, the Syncrino is light, thin and very fast drying. Its slim, fuss-free design works well under a shell, adding a reasonable level of warmth without affecting movement. It has a deep venting half-zip, is exceptionally breathable, and is comfortable thanks to the synthetic-merino fabric blend.
Weight 212g (Men's M) | Men’s sizes S-XXL | Women’s sizes 8-16 | Sustainability Fair Wear certified; Rab a climate neutral company
Salewa Pedroc Polarlite Jacket
Best for fast hiking
The close-fitting Polarlite provides more performance than a typical fleece mid-layer. Designed for high-exertion stop-start activities, it is lightweight, fast-drying, and made from four-way stretch fabric with flat seams to ensure it is comfy and unrestrictive despite its athletic fit.
Weight 260g (Men's M) | Men’s sizes XS-XXL | Women’s sizes 4-16 | Sustainability Includes PFC-free fabric; bluesign-approved; Salewa a Fair Wear Foundation leader
Arc'teryx Atom LT Vest
The Atom LT Vest is warm and breathable. The synthetic Coreloftu2122 Compact insulation does well to dump heat when youu2019re working hard and retain it when youu2019re not, so can be worn from start to finish of a trek without having to change layers. The gilet protects the core of your body while adding minimal bulk.
Weight 210g (Women's M) | Men’s sizes S-XXXL | Women’s sizes XS-XL | Sustainability bluesign-approved
Patagonia Nano Puff Jacket
Best lightweight insulated jacket
An impressively warm and lightweight insulated synthetic jacket. This is thanks to the Nano Puff using PrimaLoft Gold Insulation Eco that does very well to close the warmth to weight ratio gap that is traditionally dominated by down. The Nano Puff is versatile too, being great as mid-layer for mountain treks or ski trips but also as an outer in milder temperatures.
Weight 337g (Men's M) | Men’s sizes XS-XXXL | Women’s sizes XS-XL | Sustainability 100% recycled shell and insulation; PFC-free DWR; Fair Trade Certified; bluesign-approved.
Mountain Equipment Kinesis Jacket
Offering outstanding breathability, fast drying times, and good weather protection, the lightweight HeliumAP outer fabric is wind-resistant but still highly breathable and stretchy. The Kinesisu2019 Octayarn Warp-knit lining provides good insulation and exceptional comfort all day long.
Weight 360g (Men's M) | Men’s sizes S-XXL | Women’s sizes 8-18 | Sustainability Mountain Equipment a Fair Wear Foundation leader