Waterproofing is the first line of defence against moisture. It is exposed to the greatest burdens through mechanical influences such as abrasion but also the effects of dirt and dust. Heavy rain and snowfall can wash off the top layer of waterproofing. Even the best waterproofing wears out with time, depending on how frequently the jacket is used. The upper layer allows in more and more rain, decreasing breathability and the functional jacket feels damp. You quickly become aware that the jacket is leaking. The “clammy” feeling comes from the diminishing effectiveness of the jacket. This is a cycle that requires regular waterproofing to refresh its effectiveness. The right time to do this is when the water stops beading on the surface of the material, instead leaving a wet stain. It’s best to also waterproof immediately after washing the jacket.