Is a Trench Coat Waterproof? And Is It Warm Enough for Winter?

A classic trench coat is water-resistant, not waterproof, and it is not a winter coat on its own. Cotton gabardine sheds a shower and stops the wind, but sustained rain eventually soaks through the cloth and the seams. Warmth comes from what is under it: a wool trench, a button-in liner or a knit beneath it takes one through a cold autumn, but in real winter cold the trench is a shell, not the insulation. If you need a coat that is genuinely waterproof, look for a membrane such as Gore-Tex or Sympatex on the label.

Is a trench coat waterproof?

Not in the strict sense, and its makers have never claimed it was. Burberry, whose gabardine defines the classic trench, describes the cloth on its own Heritage trench coats as shower-resistant. That is the honest word for it. A tightly woven twill sheds a passing shower and stops the wind, but a long, heavy downpour eventually works through the cloth, and above all through the seams, which on a traditional trench are sewn rather than taped.

"Waterproof" has a measurable meaning in outerwear. Fabrics are tested for hydrostatic head: how tall a column of water, in millimetres, the cloth holds back before it leaks. Outdoor makers treat thousands of millimetres as the starting point for a waterproof jacket. A woven cotton or wool trench is not built for that test. It is built to breathe, which a rubberised raincoat never did.

Why gabardine resists rain at all

The trench coat's rain resistance comes from the cloth, not from a coating. In the late 1870s Thomas Burberry developed gabardine, a tight twill in which the yarn was proofed before weaving, with lanolin in the original version, rather than the finished cloth being coated afterwards. He patented it in 1888. The result was lighter and far more breathable than the rubberised cotton of the time, which kept rain out and sweat in.

Aquascutum, founded on Regent Street in 1851, took its name from the same ambition: Latin for "water shield", after a patented weatherproof wool cloth. British officers wore its coats in the Crimean War. Between them, the two houses produced the cloth from which the officers' coat of the First World War was cut, and that coat was always a weatherproof, never a waterproof in the modern sense.

Is a trench coat warm enough for winter?

On its own, usually not, because it was never designed to be the warm layer. The First World War trench coat was a privately bought officer's weatherproof, worn over the uniform. For warmth, officers had a different coat entirely, the heavy wool British warm. The trench's job was to keep wind and rain off whatever was underneath.

That is still the right way to think of one. How warm a trench feels depends on three things.

• The cloth. A cotton gabardine trench is a spring and autumn coat. A wool or wool-blend trench, and there are many among vintage pieces, is noticeably warmer and wears well into early winter.
• The liner. Many trench coats, from the classic makers to mid-century American labels, were sold with a button-in or zip-out wool or fleece liner. On a vintage coat, check whether the liner is still there. Buttonholes or a zip running around the inside of the facing mean one was made for it.
• What you wear under it. A trench is cut with room for a jacket or a heavy knit. Over a cashmere jumper or a tailored wool jacket, a gabardine trench handles a cold, dry day better than its weight suggests, because it stops the wind.

For freezing weather, snow or a long wait outdoors, a trench is the wrong coat. A wool overcoat, a loden or a vintage shearling coat does that job, and our guide to the best natural fibre for a winter coat compares them.

Water-resistant, waterproof, membrane: how to tell what you have

What the label or cloth says	What it means in rain
Cotton gabardine, poplin or twill	Sheds showers and wind; soaks through in sustained rain. The classic trench.
Wool or wool blend	Warmer, naturally resists a light shower; heavier when wet.
Gore-Tex	A waterproof, breathable membrane of expanded PTFE bonded inside the cloth. Genuinely waterproof if the seams are sealed.
Sympatex	A pore-free polyether-ester membrane: waterproof, and breathable through the membrane itself.
Polyester or nylon shell, no membrane	Usually showerproof from a surface finish, which wears off with age and washing.

A membrane is the only reliable route to a trench that keeps out a full day's rain. Vintage examples exist: the shape is classic, and the cloth inside is modern.

Can you re-proof a vintage trench?

Often, yes. The water-shedding finish on most trench cloth wears with age and cleaning, and it can be renewed. The general method, from makers of re-proofing products, is to clean the coat first, then apply a spray-on proofer (sprays suit uncoated cloth better than wash-in products, which are meant for membranes), and set it with gentle heat. On an old cotton or wool coat, air-dry or use a hairdryer on low rather than a tumble dryer, and test on a hidden area such as the inside of the hem first. For a valuable Burberry or Aquascutum, ask a specialist cleaner before trying it at home.

So, should you buy one?

Yes, for what it is: the best coat there is for the long, changeable middle of the year, wind, showers and the cold mornings of spring and autumn, worn over a jacket in a city. A well-made vintage trench in good gabardine or wool has already outlasted its first decades, and a good one will outlast the next. Just don't ask it to be a winter coat or a mountain jacket. For both, pick by the cloth on the label.

For the coat's history from the 1910s to today, read Trench Coats by Decade.