As a general rule, clothing for hiking and trekking consists of three layers, a base layer, a mid layer and an outer layer. Utilising this three-layer system introduces versatility and efficiency into the clothing that you wear.
The best clothing for hiking is made from synthetic or merino fabrics. Cotton is not recommended for hiking clothes as it has no insulation properties and becomes heavy when wet. Synthetic fabrics repel moisture, wicking it away from your body and drying quickly, as well as maintaining a layer of trapped warmth against your skin. Merino garments retain insulation properties even when wet, and, being a natural fibre, help to regulate your body temperature in all climates.
This is worn close to the skin and is generally made up of polypropylene or merino fabrics. They trap warmth right up against your skin and are a solid foundation for the mid and outer layers for cold weather adventures. These also double as sleepwear and increase the efficiency of your sleeping bag.
These are the most versatile layers, they are comfortable to active fitting. The mid layer fits between the base layer and outer layer garments and can be used with or without these layers. Mid layers consist of garments also made from synthetic or merino fabrics such as shirts, shorts, pants and fleece jackets or pullovers.
This layer is the final frontier, it is designed to protect you and all the clothing layers underneath from wind, rain and snow. There are different grades of outer layers, ranging from those that will repel some wind and a light spray of moisture right through to hard shell jackets made from breathable fabrics that will protect you from the biggest deluge of rain
When conditions are cold, all three layers worn together work with better efficiency than a single bulky jacket alone and take up much less space in a rucksack. Utilising multiple thinner layers in this fashion also allows you to mix the combination of clothing you are wearing depending on the conditions you set out in, and allow you to easily adjust your layers during the day.