WindBorne raises $37M Series B to scale AI weather forecasting with high-flying balloons

AI weather startup WindBorne Systems has raised a $37 million Series B round to expand its network of long-duration weather balloons and scale up its AI-powered forecasting business, CEO John Dean told TechCrunch.

The round was co-led by Khosla Ventures and Galvanize, with additional investments from TransLink Capital, Lux Capital, and previous investors, and values the company at $250 million after the round.

Founded in 2019, WindBorne set out to gather a novel set of weather data with low-cost sensors and endurance balloons. The rise of AI weather forecasting models over the past four years has let the startup generate its own forecasts, something previously out of reach for most private companies because of the supercomputers once needed to simulate the atmosphere.

Today the company runs about 20 launch sites worldwide, with roughly 600 balloons in the air at any given time collecting data in hard-to-reach areas like the eye of a typhoon. It is also beginning to deploy aerial sensor packages that drop into the ocean and keep measuring as floating buoys.

The proprietary data set from this so-called planetary nervous system creates a moat for WindBorne's weather model, which also ingests data sets from government weather agencies around the world. Dean says adding balloon data makes forecasts more accurate, with stronger value per data point than satellites.

The company's main customers today are government agencies. The U.S. National Weather Service purchases its data, while the U.S. Air Force and Navy pay through research partnerships, including work on forecasting models that can run onboard ships with intermittent connectivity.

What comes next is the commercial market, starting with investment funds that use weather data to predict commodity prices and other business outcomes. Beyond compute spending and replacing the balloon network's satellite communications with a mesh radio network, the round will fund a go-to-market team to expand private-sector customers.

Galvanize partner Saloni Multani, who co-led the round, argues that integrating weather forecasts into business decisions has traditionally been expensive and difficult, and that AI changes the equation by making better forecasts worth the effort and easier to connect to decisions. Whether WindBorne can turn weather data into a lucrative business is the question the market will now watch.