How quickly do water spots and etching form, from rainwater, potentially rainwater dripping from trees?

[JDGolden]

I don’t know it for sure, but the car to my left is an old minivan, and the car to my right is a Kia Sorrento, so it seems unlikely that they would be ceramic coated

I misread that, I thought you meant in your town/city.

I still think it's trapped under the coating.