Care full whatou use. A plastic or rubber cover can generate extreme temperatures in direct sunlight. That heat will damage and fade them even more quickly.....
When I’m out for a few day trip, I use a small cover that stretches over the handle bars and seat. Keeps direct sunlight and rain off the seat too. It’s small and light and was made for a “medium sized sport bike”. Picked it up years ago, at a local bike shop.