Model comparison
GFS vs ECMWF: which is more accurate?
The GFS (American) and ECMWF IFS (European) are the two most-watched global weather models. They are built and run by different institutions, and they frequently disagree. Here is how they compare — and why the smart move is to watch both.
Side by side
| GFS | ECMWF IFS | |
|---|---|---|
| Run by | NOAA / NCEP (USA) | ECMWF (Europe) |
| Coverage | Global | Global |
| Resolution | ~13 km | ~9 km |
| Runs per day | 4 (00/06/12/18 UTC) | 2 (00/12 UTC) |
| Cost | Free and open | Open data at 0.25° |
| Medium-range skill | Strong, ~1 day behind ECMWF | Best-in-class |
Accuracy
Across most variables and lead times, ECMWF is statistically the more accurate global model. It has held roughly a one-day skill advantage — its six-day forecast is about as good as other models’ five-day forecast — driven by higher resolution and better data assimilation. The gap has narrowed since 2021 as the GFS improved, but ECMWF still leads on average.
Freshness
The GFS runs four times a day to ECMWF’s two, so in a fast-changing situation the GFS often has newer data. It is also fully free and open, which is why it powers so many apps.
Where they disagree most
Precipitation. The two models diverge most on where and how much it will rain or snow, and that is precisely where the certainty mask earns its keep — a rain signal both models place in the same spot is far more reliable than one only the GFS shows.
The verdict
For a single medium-range forecast, ECMWF is the better default. But the most reliable read comes from agreement: when GFS and ECMWF (and ICON, and the others) line up, confidence is high; when they split, treat the forecast as genuinely uncertain. Overlay both in Meteo·Models and let the mask show you which it is.