Are there any normal* circumstances under which one might see vapour coming from the AC vents of one's car? *non-broken-thing I'm wondering if it had something to do with the outside humidity and the internal temp or something. It was about 28C out, and it's a sunny, muggy day. I had the internal temp at 22. It seemed to happen only when the car was in motion; the moment I pulled over it seemed to stop but if I started back on the road, it would start up again. On the other hand, when I shut off the car today, the AC made that long, rattly, breathy sigh before going quiet. Has my AC finally given up the ghost?