Five of the Warmest Yarns for Winter Knitting Projects

Winter weather is upon us, and for those of us who live in colder regions, that means bundling up in sweaters, scarves, and knit clothes of all kinds. Keeping warm is of utmost important as the temperatures drop, and it all starts by choosing the warmest yarn for your winter knitting projects. Knitwear, by design, already has the ability to retain heat close to the body. But you can make your sweaters, scarves, hats, gloves, and blankets even warmer with the right fiber choice in yarn.

Today, many knitters still depend on wool for utilitarian purposes, but you also have the luxury of being able to pick your optimal choice of material—and whether it is light or heavy, natural or dyed, wool or hair (or even a vegan material). Check the label: The ideal yarn for warmth are comprised of lambswool, merino, cashmere, angora, alpaca fleece, qiviut or yak fibers. Wool is sourced from sheep (merino) whereas hair is sourced from other animals such as goats (cashmere and mohair), alpacas (alpaca) and rabbits (angora).

The warmth of your knitwear depends on the animals from where the yarn is sourced, the composition, and the preparatory steps from fibers to yarn. Generally speaking, the finer the fiber, the warmer the wool—that's due to the gaps between fibers, which creates a greater thermal capacity by trapping warm air in while blocking cold air out. Therefore, a coarse wool will not be as warm as a fine wool. Since merino is a fine wool, it is warmer than other wools, but not as warm as angora, cashmere, or qiviut.

For your warmest knits yet, look for yarns made of animal hair or fur, such as qiviut, alpaca, cashmere, and wool, or find specially designed synthetic fibers. Whatever you choose, shop some of our favorites in the most frequently found varieties.

Merino Wool

Wool yarn, of course, is your classic choice for warmth. It's generally durable, water repellent, and offers good insulation due to its moisture wicking properties, making it desirable for use in a variety of garments. Manos del Uruguay's Maxima comes in the brand's hallmark colors for beautiful cowls, blankets, and sweaters. What's more, you'll feel extra warm knowing that every skein is handcrafted by the women of the Manos Cooperative, a not-for-profit, WFTO-certified artisan cooperative.

Alpaca

Alpaca fibers can be very fine and soft, but also quite itchy, and thus less likely to be used for clothing. (Otherwise, it's great for knit scarves and mittens.) Generally a little bit stiffer than merino or cashmere, alpaca fibers are sometimes blended with wool to improve its draping qualities. The PacaWool Yarn from Echoview Fiber Mill is a blend of American alpaca (75 percent) and merino wool (25 percent) sourced from within the local region, therefore, it has the memory of wool with the silky feel of alpaca.

Cashmere

Cashmere is obtained from the undercoat of the cashmere goat, which only makes up about one-quarter of the total fleece. Known for its luxurious soft hand feel, cashmere is extremely fine with a similar resilience to sheep's wool, but more delicate. Jade Sapphire is a purveyor of such luxury yarns. We like Jade Sapphire's Genghis, which is 100 percent Mongolian cashmere and comes with a hefty thickness spun by hand rather than machine.

Angora

Angora comes from the undercoat of the Angora rabbit whose fibers are extremely fine, making it incredibly soft and the finest of all the aforementioned. The hair is very light and not very strong, with a low resilience. For that reason, it's often blended with stronger or more elastic materials. Joseph Galler's Belangor Angora is the most luxurious angora we know of, and it comes from the only breeder left in France who humanely grooms his Angora rabbits. The long, lofty fibers are carefully combed from the rabbits' coats and spun into downy balls. This yarn "blooms" and produces an exceptional halo for a lighter-than-air feel.

Yak and Qiviut

Qiviut is the soft down under-wool produced by musk oxen. These beasts of the wild will range over a great swath of windswept tundras, and their coats make it possible to survive the freezing arctic winters. Qiviut is eight times warmer than sheep's wool and one of nature's finest fibers—in fact, it's 30 percent more fine than the finest cashmere and is not itchy or scratchy like wool. Because of its highly sought-after qualities, qiviut comes at the highest price point of all the aforementioned. Yak fiber, comparably, is produced from a similar animal and their Tibetan nomadic herders—but considerably more affordable. Myak's Baby Yak yarn is sustainably harvested from the downy undercoat of baby yaks and spun in a cozy worsted weight for all of your winter accessories.