Why does rolling down opposite windows create a breeze? If, while driving, I roll down both of the front windows an inch or two, it mainly creates some turbulence around the window. By symmetry we shouldn't really expect anything different.
However, if I roll down the left front window and the right rear window an inch or two, it creates a breeze blowing from the front-left to the rear-right and not much turbulence at all.
What causes the breeze to form?
 A: As the air flows around the various surfaces of the car, its pressure against the surfaces varies. Obviously the windshield will experience a significant positive pressure, and the trunk will (generally) experience negative pressure, but the pressures differ on all the surfaces.
For example, a number of airplane instruments need a source of "static pressure" to function. It isn't enough to just pick a convenient point on the skin of the airplane and run a tube to that point; the point must be carefully selected so as to minimize the effects of the air stream on the pressure at that point.
For your car, apparently the pressure at the top of the front window is significantly higher than the pressure at the top of the rear window. This is driven by the general and detailed shape of your car's body, and how the air flows across it. For example, a Civic Sedan I drove did exactly what you describe; a Golf Hatchback was much noisier, had less airflow, and in fact would at times thrum like an enormous blown soda bottle.
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Why does rolling down opposite windows create a breeze?


