The concept of ‘layering’ is key to choosing the correct clothing for outdoor sports and activities throughout the seasons. Unless you wish to confine your riding or running to sunny days only, or are lucky enough to live in a rain-free part of the world, you will need to invest in a selection of clothing that helps keep out the elements while at the same time allow heat and moisture generated by exertion to escape.
Base layers are intended to serve as the foundation of your layered wardrobe, and are thin, form-fitting garments worn next to the skin. Base layer garments serve two purposes – to keep you dry by transporting moisture away from the body to the outer surface of the cloth (a process known as wicking), and to keep you warm in cold conditions by trapping a layer of air against the skin, which warms up to provide insulation.
The type of base layer you choose will depend on the conditions you are active in and how important each of the above is to you – a light, sleeveless mesh base layer, for example, will aid moisture management in hot weather, while the thermal properties of an insulated, long-sleeve base layer will keep you warm in winter conditions.