Some challenges remain for draught areas apparently:

“Meteorological drought is defined as a shortfall in precipitation over a certain time period, typically over a long period of time like months. This means that there is a lack of precipitation in a region that comes from a lack of moisture in the air. Because moisture is the first ingredient for cloud seeding to produce rain, cloud seeing cannot be used as a solution to create rain during drought conditions.”

Heather Holmes, Assistant Professor in the Department of Physics and Atmospheric Sciences Program at the University of Nevada, Reno