I know I read it here somewhere, but I cannot find it again. I have this circular shape on my windshield, only when it rains. When the wipers go over the windshield it appears. Anybody find out whats up with that ???
Yeah I've seen those circles. They are the suction impressions from those robots like what Harley says. It seems every new cars these days has them (my 97 and 02 Chevy Cavaliers had them too).
I think they may be more prominent when it rains due to condensation on the inside of the windshield. You might take a rag or something and some window cleaner and clean the inside of the windshield to remove the oils (from normal breathing).
A persons breath contains small amounts of oil that over time will build up on the interior glass and cause condensation points for moisture. It can also be hazardous when the sunlight or headlights are shining though the front of the windshield because the oily-film will refract the light which causes the glass to practically emit light in your face (blinding you).