ECMWF vs AIFS
AIFS is ECMWF's machine-learning model, running alongside the physics-based IFS since 2025. On many large-scale scores (upper-air patterns and tropical cyclone tracks) AIFS matches or beats IFS, and it runs in minutes. IFS remains better for physical detail: rain intensity, extremes and local effects, which AI models tend to smooth. Seeing both side by side is one of the best ways to judge how much to trust a pattern.
| ECMWF IFS | ECMWF AIFS | |
|---|---|---|
| Run by | European Centre for Medium-Range Weather Forecasts | European Centre for Medium-Range Weather Forecasts |
| Origin | Europe | Europe |
| Resolution | 9 km (IFS HRES) | 0.25° (~28 km), 6-hourly steps |
| Model runs | 4 per day (00, 06, 12, 18 UTC) | 4 per day |
| Forecast range | up to 15 days | up to 15 days |
| Type | Physics-based NWP | Machine learning |
| Also called | European model, Euro, IFS, ECMWF HRES | ECMWF AI model, Artificial Intelligence Forecasting System |
| Strengths | Large-scale pattern and storm track 3–10 days out, pressure systems, medium-range temperature. | Very competitive large-scale skill, notably tropical cyclone tracks; fast and consistent run-to-run. |
| Weaknesses | A 9 km grid still smooths narrow valleys and coastlines; convective showers are parameterised, not resolved. | Tends to smooth extremes; rain intensity and local detail are less reliable than its pattern. Output is 6-hourly, without gusts. |
Key differences
- Pattern & tracks: AIFS is highly competitive and often more consistent run-to-run.
- Rain & extremes: IFS is generally more realistic; AIFS tends to under-do peaks.
- Same data, different brain: both start from ECMWF analyses, so agreement between them is less independent than ECMWF vs GFS.
Questions
Is ECMWF or AIFS more accurate?
AIFS is ECMWF's machine-learning model, running alongside the physics-based IFS since 2025. On many large-scale scores (upper-air patterns and tropical cyclone tracks) AIFS matches or beats IFS, and it runs in minutes. IFS remains better for physical detail: rain intensity, extremes and local effects, which AI models tend to smooth. Seeing both side by side is one of the best ways to judge how much to trust a pattern.
Which is the European model and which is the American model?
The "European model" is ECMWF (IFS, and its AI sibling AIFS). The "American model" is NOAA's GFS. The German model is ICON, the Canadian model GEM, the UK model UKMO and the French models ARPEGE/AROME.
Where can I see ECMWF and AIFS side by side?
On every MeteoStack city page: the stack shows ECMWF, AIFS and up to ten other models hour by hour, with their median consensus, spread and rain odds. It is free and works for any place on Earth.
More comparisons
ECMWF vs GFS · ECMWF vs ICON · GFS vs ICON · ECMWF vs AIFS · ECMWF vs UKMO · GFS vs GEM · ECMWF vs GEM · ICON vs ARPEGE · GFS vs AIFS · UKMO vs GFS · ECMWF vs JMA · ICON vs UKMO · ECMWF vs ARPEGE · GFS vs JMA