The Patagonia Women's Capilene Lightweight Bottoms are better than your average pair of long-johns. The woven grid pattern keeps your warmth next-to-skin; this fabric is soft, but also allows for breathability and moisture wicking. This base layer fits under your pants and will keep you warm all day and all night long. Want more function from them? Wear them as leggings under your favorite long sweater or dress.