Use a car cover. I often use the smaller one that covers the cockpit only. It is handy, too, when parking in a carpark. Be careful of displaying the parking ticket though !
I have a small clip ion the bottom inside of the screen to hold the ticket and hook the front of the cover up to make it visible. I take a photo of it in place. You could use a tax disc holder. Beware the over zealous private parking barstewards.
