I had the exact same thing happen to my car a month ago. It was parked under a carport with my wife's car right next to it. We came outside to leave, and my car was wet on the hood, top and hatch. There was no water on the floor around it, or on the sides of the car. There was also not a drop on the wifes car parked less than 3 feet away. I am still perplexed. I hope you figure yours out. I have no valid solution as to how mine got that way.