The warmest winter scarves are usually made from cashmere or merino wool. These natural fibers – from the cashmere goat and the merino sheep, respectively – not only hold in heat but are also supremely soft and comfortable to wear. For winter sports and hiking, a treated 'polar fleece' scarf made from a blend of synthetic materials is usually preferred. That is because these pieces trap body heat while wicking away moisture and repelling snow and rain.