In the past I thought a breeze of wind was "made" from a large amount of air molecules going all the same direction in the same speed. But it's not like that, actually this voted answer, this site, this other site say actually air that seems still (no wind), the particles are moving at 500 m/s average. This dwarfs completely the biggest winds on earth as said by the voted answer linked before.
I'm sure wind speed and direction (velocity, in one concept) is made out of somehow "averaging" velocity of air molecules. I'm not sure how exactly.
Let's suppose at a certain location I measure 20 m/s speed of wind (say pointing to north, doesn't matter). Would it be correct to say that if you take the linear momentum of all particles in the air at that location (adding the momentum of every particle) and then divide by the total mass (to get velocity units) that would be approximately what one would call "wind velocity".