Rainmaker Raises $100 Million to Scale Drone Cloud Seeding

Rainmaker Technology Corporation raised $100 million in a Series B round announced Sept. 21, bringing the drone-based cloud-seeding startup's total funding to $131.3 million. The company's own announcement did not name a lead investor, listing NOA VC, Upfront Ventures, DCVC, Lowercarbon Capital and Dream Ventures as participants instead.

The round follows a $25 million Series A that Lowercarbon Capital led in May 2025, itself built on a $6.3 million seed round in 2024. Rainmaker, based in El Segundo, California, is run by founder and chief executive Augustus Doricko, who has described the company's goal as making "more of Earth habitable" through weather modification.

What the drones actually do

Rainmaker flies weather-resistant drones into winter storm clouds and releases silver iodide, a compound whose crystal structure resembles ice and gives water vapor a surface to freeze onto. Once the resulting ice crystals grow heavy enough, they fall as rain or snow. Most commercial cloud seeding today still uses crewed aircraft or ground-based generators; Rainmaker's pitch to investors is that uncrewed drones can fly more precisely and more often.

The company says it became the first private operator to physically validate cloud-seeding results, recording 82 distinct radar signatures over four months in 2026 that it ties directly to seeding flights, together accounting for more than 145 million gallons of additional precipitation. In one three-hour window near Homer, Alaska, this summer, Rainmaker says a single seeding operation produced 19 million gallons. Rainmaker is targeting a cost per acre-foot of water competitive with desalination and fallowing agreements in time for the November 2026-to-April 2027 seeding season.

1. 2024 seed6.3 $ millions
2. 2025 Series A25 $ millions
3. 2026 Series B100 $ millions

Source: Rainmaker company blog, accessed 2026-09-28

A federal watchdog's number doesn't match the pitch

A 2024 Government Accountability Office review, cited in Fast Company's report on the round, found that existing cloud-seeding studies showed additional precipitation ranging from zero to 20 percent, constrained by limited data and natural weather variability that makes any single storm hard to use as a control. The GAO said silver iodide appears safe at current usage levels but that the effects of much wider deployment remain uncertain.

Cloud seeding cannot manufacture precipitation from a clear sky; it can only nudge storms that are already forming to drop more of what they were already going to drop. That is also what makes Rainmaker's radar-signature claims hard to independently check: separating water that fell because of a seeding flight from water that would have fallen anyway is, in the GAO's telling, still an open scientific problem rather than a solved one. Rainmaker's 82 claimed signatures are the company's own count, and its methodology has not been reviewed by the GAO or published in a peer-reviewed venue as of this round.

Rainmaker's new funding compares with two other El Segundo-area climate and energy startups The Terminal has covered this month: Bluecore Energy's floating-reactor seed round and Light's embedded-electricity Series A, both also pitching infrastructure-scale climate bets to venture investors who are pricing the technology years ahead of independent verification.

The November-to-April season Rainmaker is racing toward is the next point at which its cost and precipitation claims meet an outside test: if seeded storms this winter produce water at a cost competitive with desalination, as the company has told investors it expects, that is a figure regulators and downstream water users, not Rainmaker's own radar count, will be positioned to check.