The temperature part I cannot explain but it sounds like you have a pretty serious air leak. That is the only thing that explains the noise only at high speeds. The higher the vehicle speed, the higher the wind speed.
Try using painters tape and put stripes of tape about a 18 inches long all around the windshield so that all the window molding is covered. Then confirm the noise is gone. You can then remove the tape one piece at a time until it comes back and you know where the noise is coming from.
Again, this doesn't address that it only happens in the summer other than the fact that it could be the rubber molding expanding in the heat. So taping the windshield will cover the opening and you will then be able to find it.
Friday, July 5th, 2019 AT 1:31 PM