The middle vents are never "hot." It's just that they aren't as cold as the side vents. It's still cold enough to make my glasses fog when I get out of the car, but you can tell that there's a difference. I keep mine set to 71 because that's the temp where the vent blowing on my left hand starts to get cold enough to make it hurt. You can put your hand on the dash and feel that it's quite hot. The temperature difference is quite noticeable just going under an overpass. That couple of seconds of shade is enough to feel the difference. Same with driving into the sun vs having the sun at your back. If I increase the fan speed, it overcomes the heating effect from the dash.