Random variability of wind patterns

[Blenton]

I've been wondering lately why the air currents don't travel in the same direction. The Earth spins constantly and each side is given roughly equal irradiance from the sun, so why does the wind not simply follow this direction (on a macro scale) of heat input? Instead it seems to mix quite randomly around the globe.

 

[matthyaouw]

It may seem chaotic at a casual glance but it does follow large scale patterns. see here http://www.physicalgeography.net/fundamentals/7p.html

Don't forget there'll be local variations too, for example winds created by the rates different land/water surfaces heat in the sun.