I had a similar issue with my 2010 windshield. The wind had to be in the right direction for it to happen, so it was hard to recreate on demand, but was really annoying when the whistling started happening. I put strips of duck tape on the drivers side bottom portion of the windshield and up the side. Finally found the spot, but never knew exactly where it was because the last time I put tape on I did a bunch before a cross country trip back in 2013. All the tape has weathered off and the noise has not reappeared for whatever reason.