U.S. Air Force buys weather data from smart balloons

The U.S. Air Force has awarded WindBorne Systems, a California startup that flies a fleet of self-steering weather balloons, a contract worth up to $48.7 million to supply atmospheric data for military weather forecasting and mission planning.

The contract, awarded on Sept. 29, covers continuous, global and targeted vertical profiles of the atmosphere, from the surface up to the stratosphere, according to the Department of War. The work runs until Sept. 30, 2033. The U.S. Air Force obligated about $1.7 million in fiscal 2025 and 2026 research and development funds under the first task order, which meets the contract’s required minimum purchase, so the rest of the $48.7 million ceiling will only be spent if the service places more orders.

The contract was awarded without competition by the Air Force Life Cycle Management Center at Hanscom Air Force Base, Massachusetts. The notice does not say how much data the U.S. Air Force will buy, which regions it will focus on, or whether it will cover WindBorne’s own forecasts as well as its raw measurements.

WindBorne, founded in 2019 by Stanford University graduates and based in Redwood City, builds what it calls Global Sounding Balloons. Each weighs less than 1.4 kg (3 pounds) at launch and carries solar-powered sensors that measure temperature, humidity, pressure and wind. Unlike standard weather balloons, which rise for a couple of hours over their launch site before bursting, WindBorne’s balloons stay aloft for weeks and repeatedly climb and descend between about 1 km and 20 km (12 miles), sending data back by satellite.

The balloons have no engines. They steer by changing altitude to catch winds blowing in the direction they need, which lets the company send them toward specific areas. That is what the contract means by targeted profiling: measurements over places the U.S. military cares about, including oceans and remote regions where few weather stations exist and traditional balloons cannot be launched.

The company says it keeps about 600 balloons in the air at any time from 20 launch sites around the world, TechCrunch reported in August, when WindBorne raised $37 million in new funding at a $250 million valuation. It also runs WeatherMesh, an artificial intelligence forecasting model trained partly on its own balloon data.

WindBorne has worked with the U.S. military for several years. The U.S. Air Force gave it a contract in 2021 to help build its balloon constellation and feed the data into the service’s weather cloud, and the Defense Innovation Unit and the U.S. Air Force picked it in 2022 as one of five companies for a commercial weather data prototype project. The company has also had research contracts with the U.S. Navy, and the National Weather Service buys its data, which feeds into NOAA’s main global forecast model.