Long a favorite of knitting grannies, merino wool is finding a new purpose in activewear, thanks to a group of innovative designers in sheep-abundant lands. Soft as cotton but much more breathable, it's cool in summer and warm in winter. The brand leader is New Zealand-based Icebreaker, whose popular line of T shirts, sweatshirts, trousers and jackets includes an appealing red Plant It T shirt for women ($53) and a men's felt-lined Mayfair windproof jacket ($215; icebreaker.com). Another Kiwi company, Global Culture, makes a black-and-charcoal half-zip top for men ($152) and a shirt with a profile of a heron for women ($84; globalculture.co.nz). Untouched World offers a whole collection of stylish merino active clothing, including a great pair of women's lounge trousers in colors such as black and cucumber ($173; untouchedworld.com). And the Canadian company Sugoi has teamed up with Australian wool suppliers to create the Wallaroo line, which includes a $100 half-zip pullover in poppy, black or marine for women and gray, navy or black for men (www.sugoi.com). It almost makes that early-morning run sound good.