The Tyvek Cushion Coveris appropriate for most weather conditions. Tyvek® is a revolutionary, patented fabric ideal for covering outdoor furniture. It is extremely lightweight, and therefore easy to handle, yet surprisingly strong. Outdoor furniture covers need to breathe so that moisture can escape, keeping mold and mildew from developing under the cover. These covers are stronger than most vinyl covers, yet light weight. This means the covers are easy to use (no struggling to get them on and off). Also, these patio furniture covers are able to handle temperatures from very low temperatures to very high temperatures.