Rainmaker Raises $100M Series B to Scale Cloud Seeding

El Segundo-based Rainmaker has raised a $100M Series B to expand its cloud-seeding operations and pursue a broader goal: building the technical infrastructure to understand, influence and eventually mitigate extreme weather.

The round included NOA VC, DCVC, Lowercarbon Capital, Dream Ventures and LA-based Upfront Ventures. It comes roughly a year after the company raised $25M to modernize cloud seeding — four times the capital, aimed at a far larger mission.

Rainmaker says it has generated more than 145M verified gallons of precipitation over a four-month period. During a summer research program near Homer, Alaska, one operation produced 19M gallons in three hours, according to the company. Those figures anchor its pitch that cloud seeding can shift from experimental intervention to measurable infrastructure.

The core technology pairs autonomous drones with specialized particles delivered into carefully selected clouds. Radar and predictive software determine where to operate and estimate how much additional rain or snow an operation produced. Rainmaker is packaging these elements into what it calls a "Weather Prime" — a platform combining atmospheric science, autonomous aircraft, sensors and software capable of responding to water scarcity and extreme weather.

The new funding will pay for more atmospheric scientists, meteorologists, chemists and engineers, and expand the company's research and data-collection capabilities. Rainmaker also plans to push toward increasingly autonomous operations, driving down the cost of each mission.

The economics are the crux. Rainmaker expects its cost per acre-foot of water to fall below alternatives such as desalination and agricultural fallowing in the Colorado River Basin during the upcoming water season. If that projection holds, cloud seeding starts to look less like a niche experiment and more like another piece of Western water infrastructure.

That "if" carries weight. Cloud seeding has existed for decades, but measuring its precise effects remains scientifically difficult. A successful operation requires the right cloud at the right moment, and proving exactly how much precipitation would have fallen without intervention is a hard attribution problem.

Rainmaker's next challenge, then, is not merely producing more rain. The company must make its results measurable, repeatable and credible enough for governments, farmers and communities to buy in.

The stakes grow as Rainmaker widens its ambition beyond water. The company describes cloud seeding as the first step toward eventually mitigating hail, heat and other weather-related threats — a goal that even by startup standards is unusually sweeping.

The location fits the mission. El Segundo has become a hub for startups attacking physical problems with drones, satellites and defense systems, and Rainmaker is applying that aerospace-minded approach to one of the West's oldest constraints: water scarcity.

For Los Angeles, the round marks a progression. A year ago, Rainmaker was arguing that cloud-seeding technology could be modernized. Today it claims rainfall production at meaningful scale, with the capital to push further.

California has never been shy about reshaping nature to support growth, from aqueducts to reservoirs. Rainmaker is betting the next great water project won't be built across the ground — it will fly into the clouds. With four times its previous capital, the company now has to prove those results can become dependable infrastructure rather than promising data points.