This technique is known as “laser-assisted water condensation”, where it will enable humans to have some level of control over where and when rain will fall should the atmosphere have a high enough humidity level. Researchers have already demonstrated this particular technique in field tests after sending a mobile laser laboratory which is roughly the size of a small garage over to the banks of the Rhône located near lake Geneva in Switzerland.
The research records show that 133 hours of firings that saw intense pulses of laser light sent to the air create nitric acid particles in the air which actually behaved in a similar manner to atmospheric glue, helping bind water molecules together into droplets while preventing them from re-evaporating. It takes all but a few seconds for these to grow into stable drops a few thousandths of a millimetre in diameter, making it large enough to encourage scientists to continue their research despite being too small to fall as rain.
I would suppose that this is just a matter of time before they manage to overcome that particular hurdle, what about you?