0 a person, organization, or device that spreads substances such as certain chemicals in clouds, in order to try to make them produce rain, or more rain: --
China is the world's leading cloud seeder, using an array of methods to disperse chemicals into cloud layers.
For more than 50 years, cloud seeders have been cranking up smoke machines and flying through clouds.
Cloud seeders use silver iodide - a chemical whose structure happens to resemble that of ice crystals - on which supercooled water will condense into snow.
Cloud seeders have to start with a cloud that shows at least the promise of rainfall.