Does a silk scarf keep you warm? What the science says

In short: no, a silk scarf does not warm you the way a wool scarf does — laboratory measurements are clear on that. However, among the natural fibres compared, mulberry silk is the one that lets the least air through. That is exactly what matters at the neckline of a coat in November, when the wind goes looking for the opening of the collar.

Every year, with the first truly cold days, the same question returns: can I keep my silk squares out, or should everything be put away until spring? For a long time I answered by instinct. Since reading the research measuring the thermal comfort of fibres, I answer differently — and better.

The short answer

A silk scarf is not an insulator. It does not create that cushion of still air that gives a wool or cashmere knit its warmth. But it does two things that wool does poorly: it blocks the wind, and it stays comfortable directly against the skin.

In other words: in winter, a silk scarf does not replace a winter scarf. It is worn with it, or under the coat collar when the cold is dry and the wind biting.

What science has actually measured

A comparative study published in 2021 in the Journal of The Institution of Engineers (India): Series E put four fibres to the test: mulberry silk, eri silk, wool and linen (Das, Padaki, Jaganathan & Ashoka, 2021, vol. 102, pp. 145-154, DOI 10.1007/s40034-021-00208-2). Three results are of interest to us.

• Thermal resistance — wool comes out well ahead. Mulberry silk, eri silk and linen sit lower, with no significant difference between them. Silk therefore insulates less than wool: this is not an opinion, it is a measurement.
• Air permeability — the order reverses. Linen lets the most air through, then wool, and mulberry silk the least of the four. The authors note that this low permeability has a marked effect on its thermal behaviour, and conclude that silk suits windy conditions.
• Moisture management — mulberry silk shows the best moisture transport capacity (wicking) of the four fabrics tested.

A word of caution, because it is needed: these figures relate to standardised fabrics in a laboratory, not to your square or to a particular coat. They indicate how a fibre behaves, not a guaranteed performance. But they explain well what one feels.

Three things a silk square does well in November

1. It closes the collar. Heat loss at the neckline comes less from the fabric than from the air circulating. A square loosely knotted in the hollow of the neck blocks that draught without adding bulk under an already fitted coat. It is low air permeability, put to work.

2. It can be worn against the skin. Winter knits can itch, especially on skin dried out by central heating. Silk, smooth and fine, slips between the wool and the neck. Many people who "can't bear scarves" cope very well with a scarf worn over a silk square.

3. It spares the hair. A coat collar, a hood, a thick knit: the lengths of your hair rub all day against rough surfaces. A square tucked under the collar, or knotted to hold a low ponytail, limits that friction. It is the same reasoning as at night, applied to the morning commute — and worth keeping in mind if your hair picks up static electricity as soon as the air turns dry.

What it won't do

Let's be frank: at minus three degrees, a silk square on its own around the neck will not keep you warm, and no momme weight will change that. Silk does not add bulk, which is precisely its virtue the rest of the year. If you are looking for sheer warmth, you need a knit — and the square will go underneath or over it, for hold and for comfort against the skin.

Size and momme: what really makes a difference in winter

For winter use, two factors matter: surface area (to have enough to wrap) and weight, expressed in momme. The higher the momme, the denser the fabric, the better it drapes, and the less it creases under a collar.

To go further: our guide on which size of silk scarf to choose, and the guide to momme, the unit that explains most differences in price and drape.

How I wear it under a coat

1. The flat knot in the hollow of the neck. Fold the square diagonally, roll it into a wide ribbon, wrap it twice, and settle the knot to one side. No bulk, and the collar closes over it.
2. As a scarf lining. The square against the skin, the knit on top. The warmth comes from the wool, the comfort from the silk.
3. Tucked into an open collar. For a trench or a coat worn without a scarf: the square folded into a triangle, tucked under the lapel, points inside. It is the most elegant option, and the most effective against the wind.

More variations in our guide to the eight ways to tie a silk scarf.

Care when the air is dry

Winter calls for two particular points of attention. The first: heating dries the air, and a dry fabric builds up more static. A quick pass with a warm iron on the reverse side, or simply a night laid flat on a clean surface, is often enough to calm things down.

The second: face cream and perfume. Both mark silk, especially in light shades, and the marks set if you wait. Wash by hand in cold water with a gentle detergent, without wringing; roll in a towel, then dry flat, away from the radiator. The rule hasn't changed since June, it is simply more useful in November.

Frequently asked questions

Does a silk scarf keep you warmer than a polyester satin scarf?

On insulation alone, the difference is small: neither is an insulator. The difference lies in moisture — silk transports perspiration better, while polyester keeps it against the skin, which gives that clammy feeling as soon as you step into a heated shop.

Do you need a high momme for winter?

A higher momme gives a denser fabric and a better drape under a collar, which is pleasant. But it does not turn a square into a warm scarf: the thickness gained remains far below that of a knit.

Can silk be worn directly on dry or reactive skin?

That is one of its advantages: the surface is smooth and the friction low, where a winter knit may irritate. It remains a matter of textile comfort, not a treatment; skin that genuinely reacts deserves a dermatologist's opinion.

How do you stop the square slipping under the coat?

Two habits: aim for at least 65 cm so there is enough to tighten, and choose a dense weight, which holds its fold. A flat knot settled to one side also holds far better than a centred one.

To conclude

Silk never claimed to replace wool, and that is all to the good: what it brings in November is subtler than an extra degree. It closes the openings, it disappears against the skin, it protects what rubs. The rest is the pleasure of a square you keep twelve months of the year.

Our mulberry silk scarves and squares come in sizes from 53 to 90 cm — so you can find the one that will spend the winter under your collar.

— Awa, for the StudioSoie Journal