I feel attacked

Then there’s those of us who live in the desert. We wash our cars to make it rain.

“clean”

Depends on the rain. Quick showers clear dust and dirt form the air, and sometimes the rain formed around said dust in the first place. However long, drawn out rain that lasts hours or days has usually lost the heaviest particulate by the time it stops. Additionally wind + duration can affect how much rain came down on any given side of the car, and thus how much pre-existing dirt it’s able to clean off.