DWR helps keep the garment's face fabric dry, which makes it feel lighter and warmer. This is in addition to a fully waterproof membrane like Gore-Tex that sits

DWR helps keep the garment's face fabric dry, which makes it feel lighter and warmer. This is in addition to a fully waterproof membrane like Gore-Tex that sits behind the face fabric. DWR is also sometimes used by itself on some fabrics when the manufacturer wants higher breathability than you can get with a membrane, but still want a bit of weather resistance. A popular example from Patagonia would be the Houdini Jacket.