Humans have always wanted to control the weather. Also, drones are cool. Put those together and you've got the "Sandoval Silver State Seeder," a new drone built by the Desert Research Institute which deploys silver-iodide flares to kick off rain fall. The cloud seeding drone just had its first test flight in Nevada. It didn't make any rain — it only went 400 feet up — but DRI calls it a "major milestone."
Cloud-seeding isn't really about creating weather from nothing, but more about getting it to fall when and where you want it to — it's not for ending droughts, but you could perhaps save up rain in a reservoir to help fend off the next drought.
DRI, which has permission from the FAA to fly up to 1,200 feet up to conduct its research, plans to keep testing unmanned cloud-seeding techniques and will estimate their effectiveness.