Photo by Felix Mittermeier on Unsplash (illustrative)
On 25 February 2025, the European Centre for Medium-Range Weather Forecasts (ECMWF) made its Artificial Intelligence Forecasting System, AIFS, an operational service. It runs alongside the centre's traditional physics-based model, and an ensemble version that gives a range of possible outcomes followed on 1 July 2025.
Key facts
ECMWF calls AIFS Single the first fully operational open AI weather model, and it is openly available to forecasters.
It outperforms the physics-based system on many measures, including tropical cyclone tracks, with gains of up to 20%.
Producing a forecast uses roughly 1,000 times less energy than the physics-based approach.
The ensemble version, AIFS ENS, runs 51 slightly different forecasts and improves some measures, such as surface temperature, by up to 20%.
Why it matters
Better and cheaper forecasts help people prepare for storms, heatwaves and floods. Because the model is open and needs far less computing power, national weather services with small budgets can benefit too.
Worth noting
The AI ensemble runs on a coarser 31 km grid than the 9 km physics-based ensemble, and ECMWF treats the two systems as complementary. Experts say AI forecasts of storm intensity and extremes still need work.