Car was spotless when I left home and same when I started home from the city.
No way I would not notice those bad spots on it.
I got them somewhere on the way home and if it got on it before the rain I would have seen it on the windshield but it was clear.
After I got home it was covered including the windshield with huge spots.
I guess it could have been a plane dumping fuel I'm only about 20 miles from a US Air Base where the big refueling tanker are based.