Where does wind come from? More specifically...

There are many types of wind, but simply put, wind is air in motion, obeying normal buoyancy rules. Dense, cold air moves to replace lighter, warm air, which rises. The lightest winds are drafts through cracks in doors and windows, caused when cold outside air forces its way inside to replace warmer indoor air. Wind generally becomes stronger with altitude, so wind speed is normally higher at high altitudes.