The right cloth is almost never the obvious one. Summer tailoring is wool. Water resistance is a finish, not a fibre.
| garment | the cloth | the reason |
|---|---|---|
| Summer trousers, relaxed | Linen, or linen with viscose | linen moves heat and moisture away faster than anything else; the viscose softens the creasing |
| Summer trousers, tailored | High-twist wool — fresco or tropical | it breathes as well as linen and does not crease, which is why summer suiting has always been wool |
| Raincoat | Coated polyester or nylon, or waxed cotton | the water resistance is the finish and the weave; nylon for lightness, polyester for sunlight |
| Winter coat | Dense wool melton, or wool with cashmere | wool still insulates when damp, which no synthetic does |
| Tailored jacket | Wool twill or hopsack | wool can be moulded permanently with steam. Nothing else can |
| Slip dress, bias cut | Silk charmeuse, or viscose satin | the bias needs weight to fall; polyester satin is too stiff to spiral |
| Jeans | Rigid cotton twill, or 1–2% elastane with a recovery yarn | rigid holds its shape; plain cotton-elastane bags at the knee by the afternoon |
| T-shirt | Combed cotton jersey, a little elastane at the neck | the elastane is there to stop the neckline going slack, not to fit you |
| Knitwear, next to skin | Fine merino | the micron count decides whether it itches, not the price |
| Summer dress | Cotton lawn or voile, linen, or Tencel | all three carry moisture; Tencel adds drape without viscose’s wet weakness |
| Activewear | Polyester or polyamide with elastane | they move sweat rather than absorbing it |
| Lining | Viscose or cupro | a polyester lining in a wool coat cancels out the wool |
A tailored jacket is wool because wool can be set with steam. Shoulders shaped, lapels rolled, a chest built. No synthetic can be moulded that way, which is why a polyester blazer never sits properly however well it is cut.
Summer suiting is wool, not linen. A high-twist wool breathes as well and holds a crease all day. Linen is right for a relaxed trouser and wrong for a tailored one.
An uncoated polyester is not waterproof at all. The water resistance of a raincoat lives in the coating, the membrane or the tightness of the weave. The fibre only decides weight, abrasion and how it behaves in sunlight.
A wool coat lined in polyester cannot breathe, so the wool cannot do the thing it was chosen for. It is the cheapest saving in outerwear and the one you feel every day you wear it.