How much does air wiegh?

Answer 1

What anything "weighs" is entirely dependent on its mass and proximity to an asymmetric gravitational field. In general this is gravitational field is supplied by the Earth in normal conversation, and so we equate mass and weight loosely but incorrectly. Since the gravitational field of the Earth varies from place to place, and falls with the square of distance away from the Earth's surface, air weighs differently depending whether it is near the Earth or far above.

Weight of air is also affected by temperature.

Answer 2

A square inch column of air from sea level to the top of the atmosphere weighs approximately 14.7 pounds.

Answer 3

Air does have weight, but it is very light. In general, the weight of air at sea level is about 14.7 pounds per square inch (1 atm) of pressure, or about 0.08 pounds per cubic foot.