The fabric a rain suit is constructed from is of utmost importance to your selection. In years past, a rubber or plastic rain suit would work just fine for keeping you dry if the temperature was just perfect outside. But if it was any hotter than that, you'd sweat like crazy. And if it was any colder, you'd get chilled. New, breathable waterproof fabrics set today's rain suits apart from that old-style gear. Waterproof breathable fabrics are typically constructed from several layers of material. All look like a single layer of fabric, but most have an outer face fabric, a coated or laminated membrane layer and an internal mesh layer to protect the membrane. Many are sprayed with a durable water repellant (DWR) chemical coating for additional waterproofing. While you can still buy an old-style rubber or plastic rain suit, unless you're just going to be wearing it for a few minutes here and there, you would be better off choosing one made from breathable materials.