Generally, winter months and winter sports get all of the publicity about proper layering for obvious reasons. For me, however, layering is just as important during the summer months, mainly because no matter where one goes and what one does, one will encounter long days, heat, and a lot of sun exposure. In this regard, having a reliable base layer than can keep one cool, not get soaked with perspiration, and hold up to the rigors of multi-sport activities is worth its weight in gold, especially if it does not become smelly after a long day.