What Is Merino Wool? Merino Dresses for Winter

Merino wool comes from merino sheep and has much finer fibers than ordinary wool, which is why it feels soft rather than scratchy for most people. It's warm for its weight and breathable, so it's a good fiber for winter sweater dresses, tights and thin layers worn under a dress.

If you've avoided wool because it itched as a kid, merino is the one to try again. Here's what makes it different, how it compares with regular wool and cashmere, and how to wear and wash it through the winter.

What merino wool is and why it's soft

Merino is a breed of sheep, and merino wool is the fleece shorn from it. What sets it apart is the thickness of each fiber, measured in microns (one micron is a millionth of a meter). The Woolmark Company, the organization behind the Woolmark wool label, gives merino fibers a typical range from under 17.5 microns up to around 22 to 24 microns, and says the finer the micron, the softer the fiber.

That fineness is the whole story. The prickle people feel from wool comes from coarse fibers pushing against the skin, not from wool as such. Thin merino fibers bend instead of poking, so a merino sweater feels closer to a soft knit than to a scratchy blanket. That's why fine merino turns up in base layers and knits made to sit right against the skin.

Merino also has the usual wool strengths. The fibers are crimped, so they trap small pockets of air, which is where the warmth comes from. Wool absorbs and releases moisture vapor too, which is why merino is commonly described as breathable and temperature regulating. In practice, a thin merino layer keeps you warm on a cold walk without feeling clammy once you're indoors.

Merino vs wool

Merino vs wool isn't quite a fair fight, because merino is a wool. The real comparison is merino against the broader wools used in many sweaters, coats and blankets:

• Feel: merino is soft enough to wear against bare skin. Standard wool is often prickly unless there's a layer underneath.
• Weight: merino knits can be very thin and light. Standard wool tends to be bulkier for the same warmth.
• Warmth: both are warm. Merino gives you that warmth in a slimmer layer, which matters under a dress.
• Itch: merino is much less itchy for most people. Sensitive skin varies, so a short wear at home tells you more than any label.
• Durability: coarser wool is the hard-wearing choice for coats and rugs. Fine merino knits are thinner, so they show wear and pilling sooner.
• Price: merino usually costs more than standard wool, and fine-gauge merino costs more again.

For a winter dress or anything that touches your skin, merino is the better choice. For a heavy coat, standard wool is fine and often tougher.

Wool vs cashmere (and where merino fits)

Wool vs cashmere starts with the animal. Wool comes from sheep. Cashmere is the soft, downy undercoat of cashmere goats, which is part of why it costs more. Cashmere is very soft and light and feels warmer than its weight suggests.

Merino sits between the two. Fine merino can feel close to cashmere, and Woolmark goes as far as saying it can be softer. Merino is usually the easier of the two to live with day to day. Cashmere can pill a little in friction spots, like under the arms and where a bag strap rubs, and it's best hand washed in cold water.

If you want one cozy winter dress that you'll wear a lot, merino is the practical pick. If you want a special sweater you'll treat gently, cashmere is lovely. Both pill, so neither is a "buy it and forget it" fabric.

Merino wool dresses for winter

A merino wool dress is one of the easiest ways to wear a dress through a cold spell. It's warm, it isn't bulky, and it looks polished enough for an office or a dinner. If warmth is your top priority, our guide to winter dresses that are actually warm covers other fabrics too.

Sweater dresses

A fine-gauge merino sweater dress drapes instead of standing away from the body, so it works with a belt, a long coat and knee boots. Look at the fiber line before you buy: "merino blend" can mean a dress that's mostly acrylic with a little merino in it. If merino comes first on the label, you'll get the softness and warmth you're paying for. For outfit ideas, see our sweater dress outfits.

Merino layers under a dress

This is where merino earns its keep. A thin merino long-sleeve top or slip under a wrap dress, a shirt dress or even a satin slip adds real warmth without changing how the outfit looks. Merino tights do the same for your legs, and they feel softer than most wool tights.

To keep the layer invisible, match its neckline to the dress: a scoop or crew neck under a high neckline, a camisole shape under a V or a wrap. Pick a color close to your skin tone or to the dress so it doesn't show through a lighter fabric. If a layer under a dress starts to cling in dry winter air, our guide to static cling has quick fixes.

If merino tights are hard to find in your size, fleece-lined tights are the other warm option for dresses in deep winter.

Caring for merino

Merino lasts longer when you handle it gently. Read the care label first: some merino is treated so it can go in the machine and says so, and some is hand wash only.

1. Wear it a few times between washes. Air it out on a chair overnight instead of washing after every wear.
2. Wash inside out in cool water with a wool wash or a mild detergent. Use the machine only if the label allows it, on a wool or delicate cycle.
3. Don't wring it. Roll it in a towel to press the water out.
4. Dry it flat, shaping it gently while it's damp. Skip the dryer unless the label says it's fine, because heat and tumbling can shrink and felt wool.
5. Fold it for storage. Knits stretch on hangers, especially heavy sweater dresses.

Merino will pill a little in rubbed spots, even the good stuff. That doesn't mean it's poor quality. A sweater comb or stone lifts the pills gently (fine merino is too delicate to trust to a shaver's blades), and our guide on how to remove pilling walks through it.