Air doesn't really have a true 'speed'. There is a 'transfer-of-air' speed that is dependent on pressure. Generally, the more there is a difference in pressure, the faster nearby air will move.

At the surface of the planet, all the air above you puts a pressure of 14 pounds per square inch on everything. We don't feel that, because we evolved to not feel it. You can't see it because that air presses in on every possible direction.

But air kinda has a speed.

The "speed of air" is probably best described as the "speed of sound". Sound in air, like a balloon's pop or someone's shout, is transmitted at about 770 miles an hour, or about 1100 feet per second. When you smack your hands together, someone that's 1100 feet away will hear it in one second. When a lightning bolt causes a thunder clap, five seconds later (almost a mile of distance), you'll hear it.

That's probably the best way to describe how "fast" air is.