Picnic Blanket - Weatherproof Picnic Rug 4 Person. 4 Person Picnic Blanket with Carrier, there’s always a great place to stop and enjoy a picnic. Whether you’re tucking into a picnic on the beach, park or wood, there’s no need to worry if the ground’s damp – the blanket features a waterproof PEVA backing to keep everyone comfy and dry.