WindBorne Systems is developing long-duration weather balloons that can transition into ocean buoys after landing on water, extending their data-collection mission from sky to sea. The company's CEO John Dean describes how roughly half a dozen prototype balloons have already demonstrated this sky-to-sea capability, with plans to make all future balloons waterproof within months. One balloon, Elder, set a company record of 345 days aloft after a valve redesign eliminated gas leaks at low temperatures. WindBorne operates a fleet of ~600 balloons globally, communicating via Iridium satellites, and feeds the data into WeatherMesh, an end-to-end AI weather model trained from scratch that includes full data assimilation. The balloon observations currently yield a 10–20% improvement in forecast accuracy, and NOAA found similar gains for hurricane tracking. The company plans to scale from ~600 balloons today to 4,000 within 18 months, and expects thousands of ocean buoys reporting data within a year.
