Now this is not about how pretty to look, or to dress yourself in the latest fashions when you are heading for your summit. It is about how to dress correctly so that you are not too cold, or too hot for that matter on high altitude treks.
1) Layer, Layer, Layer
The single most important thing about dressing for the cold is to layer your clothing. Wearing a thermal vest and then throwing a thick jersey is not going to keep your warm and this is where many people go wrong. Layer, layer, layer, means to generally go with three layers; a base layer, mid and outer layer. Start with a good thermal base layer. It must not be too tight that it restricts movement but at the same time, must not be loose-fitting. On top of that goes a long sleeve soft-shell zip up. Your other layer would be a warm jacket, which could be down depending on the temperatures you are going to, or a windproof, waterproof zip up jacket. Layering also needs to be done on hands and feet, one pair of thin liner socks plus hiking socks, and on your hand, thin liner gloves and thicket outer gloves. Mits are the best.
2) Don’t overdress
As strange as it may sound after reading about all the layers, overdressing so that you are too warm is problem. If your body is too warm, your natural thermostat will kick in and your body will try to cool you down a bit, with the inevitable result that you will feel cold and pile on more clothing. It is like drinking tea on a hot day – it actually cools you down.
3) Zip up
Zips on jackets, fleece and softshells is important, as they allow you to “unzip” if you need to cool down a bit, rather than pull off a later.
4) Not too tight
A lot of people make the mistake of having their clothing too tight that there is not enough room for free movement. You really need the air between the layers to warm up. If you gloves and socks are too tight, it will also cut off your circulation which is the last thing you want.
5) Avoid Cotton
Cotton is lovely in the warm summer months, but is not functional when it comes to hiking at high altitude. Cotton t-shirts absorb moisture, causing your body to cool down. As the evening approaches and temperatures drop, you will quickly find yourself clammy and cold making it harder for your body to warm up. Always buy wickable clothing that moves the moisture away from the body.
These are some basic guidelines and it all depends ultimately on the temperatures you are going to. The trick with layering is you can always add on or remove a layer.