[medwards]

Wool. That said, individuals do differ over their own personal preference between wool and cotton. I am one who favors wool year round. Part of this is a result of its look and feel. But more of it rests with the properties of wool socks. Merino wool hosiery will feel warm in the winter and cool in the summer. The nature and shape of wool fibers results in them holding a good amount of air, creating a heat insulating barrier. Yet wool breathes exceptionally well. Moreover, because wool absorbs moisture in the inside of the fiber itself (rather than like cotton where the whole fiber absorbs moisture), the surface of a wool sock stays relatively dry. In fact, its moisture absorbing power is almost twice (1.8) times that of cotton.