Rain Jackets: Membranes and Coatings

Rain jackets are key components of many hiking clothing systems because they provide a barrier against rain, snow, and wind. Modern designs frequently use laminated constructions that combine a face fabric, a waterproof-breathable membrane, and an inner lining or coating. Membranes are designed so that liquid water is blocked while water vapor can, under appropriate conditions, move outward, thereby reducing condensation. In practice, breathability is influenced by temperature gradients, humidity levels, and activity intensity.

Alternative designs rely on coated fabrics, in which a continuous waterproof layer is applied to the inner surface of the garment. These coatings may provide very high resistance to water ingress but typically restrict vapor movement, leading to more condensation during exertion. Some jackets blend membrane and coating technologies or adjust the thickness of layers to target particular use cases, such as high-abrasion mountaineering environments versus ultralight backpacking.

Seam construction and hardware are critical to waterproof performance. Taped or welded seams are used to cover stitching holes, and water-resistant zippers or protective storm flaps are added to minimize leakage at openings. Ventilation features, including underarm zippers, two-way front zippers, and mesh-backed pockets, allow users to modulate airflow and heat release.

Face fabrics are often treated with durable water repellent (DWR) finishes that encourage water to bead and roll off rather than saturate the exterior. When DWR degrades, the fabric can "wet out," reducing breathability and increasing the likelihood of condensation inside. Many sources note that even well-maintained jackets cannot entirely prevent interior dampness in strenuous or highly humid conditions. The overview here describes common construction concepts rather than ranking specific technologies.