When to repair my windshield?
You Should Repair Your Windshield As Soon As Possible
It's best to repair your cracked windshield as soon as possible, so that rain-x, wax, dirt and water won't contaminate the damaged area.
TIP: If you cant repair the windshield today, you should put some scotch tape over the outside of the damaged area and completely cover it from the elements.
The longer you wait the more discolored the damage will become. If it is raining or you just got a car wash you'll have to wait until windshield damage is completely dry.