It may be tempting to put on that big bulky jacket for your winter walk to protect you from the elements and keep you warm. In actual fact the most effective way to protect yourself from the cold is to wear multiple layers which can be added or removed depending on the conditions.
The “layering system” is essentially a way of layering clothes together to ensure you are comfortable during outdoor pursuits. This could be to keep you warm or to cool you down. Layering often only refers to tops and jackets but you can layer leggings and trousers in the same way. You will find most hikers, climbers, snow sport lovers and many other outdoor enthusiasts will use an effective layering system.
The reason wearing multiple thin layers will keep you warmer than a single thicker layer is because warm air is trapped between the layers acting as an insulator. If you were then to remove a layer you would reduce the amount of heat trapped which would cool you down.
The benefit of using a layering system is that you can prepare for many eventualities that may arise. If the weather is nice before you set out then you can pack you bag with clothing that can keep you warm and dry whilst wearing a base layer. You won’t overheat and if the temperature was to drop, or it started raining, you have what you need.
The base layer is the first layer that sits directly against your skin. A base layer has two main functions- to regulate your body temperature and wick away moisture from the skin.
A base layer is your first layer of protection against the elements and will provide a small amount of warmth. A base layer should also ‘wick’ or ‘transport moisture or sweat’ away from the body. This will help to regulate your body temperature as any moisture build up can draw warmth away from your body.
Cotton clothing is a no no as a base layer. Cotton will soak up any moisture that may build up but won’t dry out making you feel very cold. If you are taking part in a more vigorous activity, such as cycling or running for example, then wearing a base layer by itself would be suitable.
The function of the mid layer is primarily to provide insulation. A mid layer will direct any body heat that your base layer didn’t retain back into your body and help stop cold air passing through to your body.
A good mid layer will be breathable and also wick any moisture away from the body so any moisture trapped by the base layer is transported out to be evaporated.
Micro-fleeces, merino wool tops, soft shells and thin insulated jackets are popular mid layers. A thin fleece or merino wool top could be worn during milder conditions. Thicker fleece or soft shell jackets would be suitable for colder weather and if the weather is really poor, then warmer insulated jacket may be a better option. In some cases, if the weather is fair, a base layer and mid layer might be all you need.
The main purpose of the outer layer is to protect you from the wind and rain. Often the outer layer will be waterproof and breathable which will allow sweat and water vapour to escape the body and also keep you dry should it rain.
In most cases a thin shell jacket opposed to a heavy, warm jacket is all you would need as your mid layer should be working to keep you warm. If it is particularly cold or even freezing then you may consider a warmer jacket or even another mid layer.
Using a layering system will allow you to self regulate your own body temperature as you feel necessary. If you find yourself on the chilly side, then reach into your bag and pull out that fleece. It is quite likely you will build up heat as you walk or ski anyway, so if you start out cold, after a while you may feel too warm and need to reduce layers. Something you couldn’t do if you didn’t use a layering system.