Keeping warm in cold weather
When travelling to places where there are rapid changes in the weather and temperature within the space of a day, it is best to to have a layered clothing approach, Layered clothing means using many garments that are worn on top of each other, to match the needs of each situation. Wearing two thin layers can be warmer yet lighter than one thick layer, because the air trapped between layers serves as thermal insulation. When temperature turns warmer, you can then remove the top layer.
Thermal layer – against the skin
The base layer should keep you warm and wick moisture from perspiration away from the skin.
Polyester based fabrics dry fast and have good wicking qualities. They also last longer, and do not attract body odor like polypropylene (“polypro”) fabrics. Wool has fairly good wicking properties and is highly odor resistant. However, wool is more expensive and may not feel comfortable against the skin.
Avoid cotton for the inner layer in cold weather as it absorbs moisture easily and is slow to dry out.
The middle insulating layer
The mid layer is needed in cold weather to provide additional insulation. The mid layer should be more loose-fitting than the inner layer, as this leaves insulating air between the layers.
Wool is the traditional mid layer material with several good properties: it has good insulation even when wet, absorbs moisture but does not feel wet even when it holds significant moisture, and transfers moisture.
Fleece has many of the feature of wool and is lighter.
The outermost clothes that block wind or water is called the shell layer. Ideally, it should also be breathable enough to let through moisture to the outside. If heaving sweating is expected, example when jogging, one should avoid wear any shell layer garments.
Hard shell materials are waterproof and somewhat breathable.Waterproof membranes such as Gore-Tex, HyVent, or eVent, water-repellent coatings (DWR), and windproof technologies such as Windstopper, protect you from the elements without adding significant weight.
Soft shell materials are water resistant as it block water only partially. They are howerver more breathable and comfortable, thinner and cheaper than completely waterproof materials. The typical softshell jacket is typically made of stretch-woven polyester or nylon and elastane, and it can be worn as a midlayer in severe weather or as an outer layer in moderate weather. Although a fleece or insulated jacket typically provides more warmth, and a shell jacket offers more protection from wind and wet weather, the softshell provides a balance of both benefits, and its high level of breathability is excellent for aerobic activity.
Your hands and feet need layers as well. Wear inner socks under thicker socks to keep your feet dry. Fingerless liner gloves or very think wool gloves make a useful base layer for your hands.