Depends on the material used:
Polyethylene; not or hardly;
Non-woven 3 layer construction; not or hardly;
Plain polyester; yes;
Solution Dyed polyester; discolors slightly over time.
The most commonly used fabric for protective covers is polyester. There are many different quality classes of polyester available. Polyester has the following properties: polyester hardly wrinkles and does not discolor under indirect sunlight. Polyester also has high resistance to wear. Polyester is a relatively dense fabric, so it offers some protection against rain. If it is combined with a PVC or PU coating on the inside, a good product is created. Cheaper polyester fabrics are less colourfast, the better ones have a higher colourfastness. These covers are made of Solution Dyed material. However, it is inevitable that polyester will discolor over time.