Creating flowing air by directly moving the molecules in the air should be one of the easiest manipulations of matter using the force. Already flowing fluids such as air and water should be easy as well, just changing direction. Moving solid objects by overcoming their inertia is probably harder to do, but even noobs like Luke in ESB can do it with concentration. And if noobs can move a lightsabre across the room then they could easily stir up a breeze. And if masters can move starships and huge rocks then they could summon powerful winds and deflect streams of fire or simple clouds of deadly gas.
i.e. Force push is not a giant set of invisible hands. It's changing the relationship between objects, specifically their relative motion.
Edited by GrimmyV