Waterproof jackets aren’t good multitaskers. Sure, vinyl or PVC slickers are impenetrable, but while they keep rain out, they lock sweat in--making you feel clammy. One fix is the waterproof breathable jacket. The key to its success is a delicate membrane sandwiched between two layers of fabric. Unfortunately, during downpours, the outer layer soaks through, making you feel damp. And adding to the discomfort, the glue that holds the fabric layers together ends up trapping perspiration inside.