You do not need to cover your POLYWOOD furniture to keep it protected. The weatherproof frames can easily handle harsh climates in any season. However, covering your furniture will extend its life and make cleaning easier and faster.
Although POLYWOOD doesn't sell furniture covers directly, you can purchase covers from retailers such as The Cover Store. To look for the cover that fits your furniture best, all you need are the dimensions of the piece(s) you want to cover up.