I've been meaning to get a pair for a while to match my cape; I'm tall enough that rain can sneak under it and hit my lower legs (apart from road spray). I'd imagine it will keep the water off for a while, but I find even freshly-proofed waxed cotton wets out in heavy rain; the advantage of using it for a cape is that the bit that gets wettest is held away from your body. I'd use them for commutes in civvies, but I wouldn't have thought they'd be ideal for long spirited rides in the wet.