Windproof

If cold air penetrates our clothing, it replaces the thin, warm layer of air next to our skin. This is known as convective heat loss, the transfer of heat from our skin into the air (more commonly known as "very damn uncomfortable").

That's why windproof fabric is so important: it guards us from the wind chill effects of cold winds, that disrupt our body heat.

Breathable AND windproof?
A look at Gore-Tex® membrane under an electron microscope shows a structure similar to that of a thick hedge. The wind gets trapped in the endless number of tiny branches and is kept away from the body. That means that the insulating layers of air around the body are maintained. Even with a strong head wind on the way up the highway.