A Startup’s Weather Model Beats Europe’s Best—Here’s How

A small startup called Windborne Systems just released a weather forecasting tool that, on several key measures, outperforms the gold-standard system run by a consortium of European governments. The secret? Better data, fed smarter into deep learning models.

Founded by Stanford students in 2019, Windborne started by designing a superior weather balloon to sell data. Then, when AI forecasting models emerged in 2022, the team realized they could build their own. Today, the sixth version of that model, WeatherMesh, is out. The company says it beats both traditional and AI forecasts from the European Centre for Medium-Range Weather Forecasting (ECMWF), long considered the world leader.

Put simply, WeatherMesh 6 is as accurate five days out as a standard forecast is the day before—especially on surface temperatures. It also updates every hour, not every six. Its resolution reaches 3 kilometers in Europe and the continental U.S., where data quality is highest.

Traditional forecasts rely on physics models that need supercomputers and hours to run. AI models, including those from Google DeepMind, are faster but often lower-resolution and less accurate over longer periods. Windborne’s edge comes from a unique combination: building its own model while collecting its own data. The company keeps about 400 balloons aloft at any time, launched from 15 sites globally. Improvements in WeatherMesh 6 stem from better ways to feed balloon readings directly into the model.

“I don’t understand the business model of being an AI weather company without a data set advantage,” CEO John Dean told TechCrunch. The ECMWF’s strength has long been “data assimilation”—turning scattered sensor inputs into a usable picture. Most AI models still depend on data from the ECMWF and NOAA. But Windborne is now bypassing that reliance. Head of AI Joan Creus-Costa says direct data ingestion from their balloons drove the latest leap. It took a year of tuning a transformer-based model to keep it stable.

Dean predicts that if the company removed ECMWF’s initial conditions, “we would actually still do pretty good.”

Last year, a United Airlines jet hit one of Windborne’s balloons. The plane suffered minor damage; no one was hurt. Now, the balloons carry transponders that report their location via the global aviation surveillance system to reduce risks.

Windborne has raised $25 million at an $85 million valuation. It sells balloon data to NOAA, the U.S. Air Force, and Navy, plus forecasts to investors and commodity traders. Still, Dean says the focus remains on building infrastructure, not commercial products. “I’m not trying to invest a massive team into building a SaaS product if the way people want consumer information two years from now is through an agent,” he said.