Mid layers come in many different guises. Worn over a base layer (which sits next to the skin and wicks sweat away from you) and under an outer layer (one that’s wind- and waterproof), their primary role is to provide warmth. Fleece has traditionally been the most popular mid layer choice. But there’s now a much wider range available, including soft shell and synthetic fibrefill, which perform functions traditionally done by the outer and base layers. Different types offer different benefits, so it’s up to you to decide what’s most important to you. Greater warmth, waterproofing, wind protection, value for money, weight, packability, durablility, drying time and softness are just some of the things to consider.
Check the weight of the garment and how windproof, waterproof or insulating it is. Microfleece is the lightest fleece available, but gives less warmth than heavier fleece. Windproofed fleece and soft shell fabrics are not as warm or breathable as other options, but are more weatherproof. Synthetic fibrefill is warm even when wet and is lightweight.
Consider how the jacket will work when worn with a rucksack. Can you still reach the pockets or are they obscured by the hip-belt? Do you want a hood or a high collar? Can you work the zips and drawcords with gloves on? Over-the-head smock designs save weight but can be awkward to get on.
It should fit well and give you freedom to move. If it’s too baggy, it won’t keep you as warm as it should. If it’s too small you may not be able to wear it over other layers. The cuffs should fit snugly to prevent draughts. Pockets: Are they big enough to fit a map or guidebook in? Mesh-lined ones will save on weight and aid ventilation.
These help adjust the jacket to fit you, but can be annoying if they dangle and flap around in the wind. Additional features: Look out for detachable or fold-away hoods, chin guards to protect you from cold metal zips and draughts, two-way zips for additional venting and large zip pulls for easy use with gloves on.