When outdoors we all see and feel the effects of the weather and it can have a big influence on our experiences. Whether your scaling the Weisshorn or trekking the length of Hadrian's Wall, having the right clothing with you can make the difference between a tremendous adventure and an uncomfortable ordeal.
You will likely have heard about using a layering system for your outdoor clothing. The basis thought behind this is that having a number of layers allows you to easily regulate your body temperature by adjusting your clothing. In the guide below we will discuss the purpose of the different layers within the layering system and also give some examples of them.
As the name suggests, this is the layer that you wear next to your skin. The purpose of this layer is to wick moisture, (sweat) away from the body. We want this to happen because having wet skin cools our bodies down significantly. This is fine in hot climates but in cold weather it can lead to you becoming very cold, very quickly. We always avoid wearing cotton whilst outside for this reason. Cotton holds on to moisture so after an active trek it is likely to become soaked. This produces a cold, clammy layer that will cool the body down.
Baselayer materials generally fall into two categories, wool and synthetic.
Synthetic baselayers have the benefit of being faster drying than wool, are more durable, none itchy and are usually cheaper. The downside to synthetic is that they do tend to hold on to odours which are difficult to get rid of. Many manufacturers produce odour resistant fabrics which help with this issue.
The majority of wool baselayers are made from Merino Wool which is moisture wicking , quick to dry and less itchy than traditional wool. Merino holds more moisture than synthetic fabrics but still insulates whilst it is wet, unlike cotton. It is also soft and naturally odour resistant, meaning you are likely to need less items of clothing with you if your away on an expedition. It does have the downside of being more expensive than synthetic layers and tends to abrade and tear a bit faster, making it less suitable for activities such as rock climbing.
In cold weather we tend to look for thicker baselayers which will provide more insulation. Merino wool has the edge on synthetic base layers here as it offers great insulation for its weight whilst still helping to regulate your body temperature.
There are a few key features to look out for in baselayers
Chest Zip - A zip is an easy and effective way to regulate your body temperature.
Collar - A high collar provides additional insulation.
Offset Seams - offset shoulder seam help to reduce chaffing if carrying a rucksack.
Fit - A baselayer is most effective if it is close fitting.
Length - Longer baselayers are a good idea for active use where the hem may be prone to lifting.
Thumb Loops - For cold weather baselayers thumb loops stop the sleeves from riding up and keep your hands warmer.
The purpose of a midlayer is to provide insulation. It does this by trapping pockets warm air around the body. As with baselayers, a mid-layer wants to be made from wicking materials to aid breathability. The most common mid-layers are fleeces or thick wool layers which trap large amounts of heat whilst remaining lightweight. In some conditions, lightweight, insulating layers may also be worn as an alternative, as these are generally warmer for their weight. Softshells can make good alternative mid-layers as they are more versatile, soaking up less moisture than a fleece and also offering some wind and rain resistance.
A shell is the outer part of your clothing system and directly protects you from the wind and rain. The most effective outer-shell is a breathable, waterproof as this ensures that your clothing system dos not become wet and also stops the wind removing the warm air from your insulating layers. Though a waterproof is not as breathable as your base and mid layers it will allow moisture to escape, ensuring your inner layers stay dry.
An alternative outer shell that is becoming more popular is the softshell. This is because softshells provide good wind resistance, are more breathable than waterproof jackets and also tend to be more comfortable to wear. The downside to them, however, is that they are not waterproof and cannot be relied to keep you dry in heavy rain.
Another shell option that is popular with runners and cyclists is a wind shirt. This is a very thin layer that protects the wearer from the wind whilst offering only minor insulation, ideal for aerobic activities where you are generating large amounts of body heat.
In cold temperatures or during inactivity it is often necessary to have a fourth layer that provides additional insulation. With an insulating layer it is important to balance warmth against weight and bulk.
Clothing insulated with goose or duck down offers the best warmth to weight ratio available and is also incredibly packable. The downside to down however is that when it becomes wet the feathers stick together and it looses its insulating properties. Some companies have begun to introduce hydrophobic down which is water resistant and dries out faster.
Synthetic insulation, such as Primaloft, works in the same way as down but is less effected by moisture. Though not as compressible, it still provides excellent warmth for weight.
On many occasions you may only wear an insulating layer whilst inactive as they provide such effective insulation that you would overheat wearing it during activity.
Whilst the outer fabrics of insulating jackets do offer some water and wind resistance, in wet weather it is best to wear them beneath your shell layer to protect them. This is not possible with very heavyweight down and synthetic jackets due to their bulk though generally these jackets are needed in very low temperatures where rainfall is unlikely.
The above principals of layering apply to legwear also though our legs usually require less insulation than our upper bodies. Needing to have a fourth, insulating layer for your legs is only likely to be required for extreme cold or for long periods of inactivity in cold temperatures.