Rainmaker raises $100M to scale drone cloud seeding across the American West

Why it matters

Rainmaker is attempting to turn cloud seeding from a difficult-to-measure service into water infrastructure priced by verified output. The $100M round funds the science needed to prove that model.

Augustus Doricko (@ADoricko) said in a thread on X on September 21st that Rainmaker has raised a $100M Series B to expand its atmospheric research operation and scale a drone-based system for producing additional rain and snow from existing storms.

https://x.com/ADoricko/status/2102065586045915191

Doricko, Rainmaker's founder and CEO, attended the University of California, Berkeley, studied physics and later became a Thiel Fellow, according to Rainmaker's press materials. Before starting Rainmaker, he developed software to help Texas water-well operators manage usage and regulatory reporting. The experience led him toward a harder supply problem: improving how much water reaches farms, reservoirs and ecosystems in the first place.

NOA VC, Upfront Ventures, DCVC, Lowercarbon Capital and Dream Ventures invested in the Series B. Rainmaker did not identify a lead investor in its announcement. The round follows a $6.3M seed financing in 2024 and a $25M Series A led by Lowercarbon in May 2025, bringing Rainmaker's disclosed funding to at least $131.3M.

Building a measurable cloud-seeding operation

Rainmaker flies weather-resistant drones into suitable clouds and releases small quantities of silver iodide, which provides particles around which ice crystals can form. Those crystals can grow and fall as rain or snow. Cloud seeding requires an existing weather system with the right temperature and moisture conditions; it cannot create clouds or precipitation from clear skies.

The commercial pitch depends on measurement. Operators have used cloud seeding for decades, but separating precipitation caused by seeding from precipitation that would have fallen naturally has remained difficult. Rainmaker combines drones with radar, satellite data and precipitation-estimation software intended to identify visible seeding patterns and calculate the resulting water.

Rainmaker says it recorded 82 such patterns over four months in 2026, representing more than 145M gallons of additional precipitation. That figure remains a Rainmaker calculation. In an August 24th validation report, Rainmaker estimated that seven flights near Homer, Alaska, produced between 45 and 65 acre-feet of precipitation on August 23rd. Rainmaker's mean estimate of 57.6 acre-feet equals about 18.8M gallons.

The underlying technique has support from academic fieldwork. The 2017 SNOWIE experiment in Idaho used radar, aircraft instruments and ground measurements to trace silver iodide released by an aircraft through cloud formation and snowfall. The National Center for Atmospheric Research says researchers measured additional snow attributable to seeding under suitable conditions.

That evidence does not make precipitation enhancement predictable across every storm or watershed. A 2024 U.S. Government Accountability Office assessment found that studies estimated additional precipitation ranging from zero to 20%, with results constrained by limited data, natural weather variability and the availability of seedable clouds. The GAO also found that current silver iodide use did not appear to pose an environmental or health concern at existing levels, while cautioning that the effects of much wider deployment remained uncertain.

The round finances a research lab, not just a larger drone fleet

Rainmaker plans to hire atmospheric scientists, radar and satellite specialists, aerosol researchers and materials scientists. The work will focus on which clouds to seed, when to fly, how much material to release and where additional precipitation would deliver the most value within a watershed. Rainmaker also plans to support projects at U.S. national laboratories and universities.

That expansion pushes Rainmaker beyond operating cloud-seeding missions for water agencies and agricultural customers. In Doricko's Series B announcement, he described cloud seeding as the first application of a broader weather-modification platform covering sensors, autonomous aircraft, atmospheric models and new seeding materials. Rainmaker's longer-term plans include work on hail and other environmental constraints on productive land.

Rainmaker currently lists operations in Utah, Idaho, Oregon, California and Colorado. Rainmaker says additional drone crews can work in parallel, increasing production while spreading hardware and research costs across more acre-feet of water.

The immediate commercial test arrives during the November 2026 to April 2027 operating season. Rainmaker expects its internal cost per acre-foot to fall below most sources of incremental water, including desalination and programs that pay farmers to leave fields unplanted. Rainmaker has not published customer prices or field data that independently establish that comparison, so the cost claim will turn on output measured across a full season rather than a handful of favorable storms.

The $100M round gives Doricko the capital to build the scientific organization required to answer that question. Investors are financing a wager that better aircraft, denser atmospheric data and continuous field operations can turn a conditional weather intervention into repeatable water infrastructure.