Rainmaker has raised a $100 million Series B to expand the research operation behind its cloud-seeding service. The company works with water agencies, governments and corporate partners seeking more water from existing storm systems. Its purpose-built drones disperse small amounts of silver iodide inside suitable clouds, encouraging ice crystals to form and fall as rain or snow. NOA VC, Upfront Ventures, DCVC, Lowercarbon Capital and Dream Ventures participated.
Forecasting software first identifies a viable seeding window and guides site planning and deployment. An instrumented drone then targets supercooled water and releases the seeding material. After the flight, Rainmaker uses radar and satellite monitoring to estimate the added precipitation. That measurement is central to the business: the company is selling an attributed water outcome, not merely a drone flight.
Rainmaker markets the operation to state and local water authorities, federal and international governments, and corporate partners. Intended uses include building mountain snowpack, replenishing aquifers and reservoirs, supplying farms and cities, and stabilizing hydroelectric output. The company says it currently operates in Utah, Idaho, Oregon, California and Colorado.
Rainmaker says four months of operations produced 82 distinct radar signatures corresponding to more than 145 million gallons of additional freshwater. It also attributes 19 million gallons of precipitation to roughly three hours of August flights near Homer, Alaska. Those are company-reported measurements. Independent experts quoted by the Associated Press describe cloud seeding as an imprecise technique that can modestly increase precipitation under limited conditions, often produces no result and cannot create a storm without existing clouds.
The new capital will fund more atmospheric scientists, radar and satellite specialists, and materials researchers. Their work will examine which clouds to seed, when to intervene, how much material to release and where the resulting precipitation should land. Rainmaker also plans to support research at national laboratories and American universities, putting much of the Series B behind the validation and repeatability of each operation.
Rainmaker says its cost per acre-foot falls as it produces more water, while additional drone teams can work in parallel. Its next disclosed benchmark is the November 2026 through April 2027 season, when the company expects that cost to fall below most alternative sources of new supply, including desalination and compensating farmers for leaving fields unplanted.