I have the same problem

Stupid water marks. I've tried Meguiars cleaner wax, and bought a good chamios and meguiar cloth that absorbes water well, but nothing I've tried is getting rid of them. Always parked under shade and not washed in hot weather, I'm not sure how the hell I got them! Will try a cut and polish next. Goodluck with it all, sucks to have stains.