Most lower-quality synthetic rattan furniture has colour applied only to the outside of the weave – like a paint – so it should be covered in winter and during sunny periods, to avoid bleaching and loss of colour. Poorer quality items can also split or break in a hard frost – even (cheaper) synthetic models.
High-quality synthetic rattan is made to stand up very well to winter conditions. There is little benefit in covering your synthetic rattan furniture for most conditions, but if you live in an area with regular hard freezing and snowfall, covering outdoor furniture is recommended by some manufacturers, as a precaution during the harshest seasons. It is a simple safeguard to keep the pristine look for longer.
Some owners stack their outdoor furniture and cover it securely with one large cover. This protects it from being moved by very high winds.
Some companies manufacture covers specifically for their furniture items. Since some modular sets are meant to be set in particular configurations, you can buy covers made to go over your furniture in place, so you don’t need to move it anywhere.