Compare ECMWF, ICON and GFS forecasts

ECMWF IFS, DWD ICON and NOAA GFS are different forecast models. Weather Pro offers four model choices through Open-Meteo, including two ECMWF IFS options. Compare their hourly values for the same location and period; a model’s name or grid spacing alone does not establish which forecast will be right.

Compare the same question

When two forecasts disagree, first check that they describe the same coordinates and the same local period. A city centre and a saved point outside the city are different locations. Tomorrow afternoon and the next twelve hours are different time windows.

Keep the display interval and units consistent as well. A three-hour rain accumulation should not be compared directly with a single hourly amount. Wind in knots and wind in kilometres per hour can look different while describing the same speed. The hourly forecast guide explains those distinctions.

ECMWF IFS, DWD ICON and NOAA GFS in Weather Pro

Weather Pro is in development with four named options through Open-Meteo:

• ECMWF IFS 9 km
• ECMWF IFS 0.25°
• DWD ICON
• NOAA GFS

Keep the complete model name with your comparison. The two ECMWF choices are separate options, and a provider’s name alone does not tell you which one you selected. Open-Meteo supplies the data used by the app; it does not make all of these choices the same forecast.

The Open-Meteo model documentation describes the service’s available models and fields. The choices offered by Weather Pro are the four listed above, rather than every model supported by that service.

Look at the hours, not just the headline

A daily summary is useful for finding a period of interest. It can hide differences within the day, however. Two models might suggest a similar daily temperature range while placing a wetter or windier period in different hours.

Start with the period relevant to your plans. Compare temperature, precipitation, wind and gusts across those hours. Ask whether the models broadly describe the same progression, then identify where they diverge.

For rain, check both the amount and the period it covers. In Weather Pro, a three-hour accumulation ends at its column’s hour. A difference in timing is easier to understand when each value is compared on that same basis.

Check freshness and available dates

The app’s forecast update time tells you when the forecast was downloaded. It is not a guarantee that every model was produced or updated at that exact moment. Keep that distinction in mind when comparing newly downloaded data with an older saved forecast.

Forecast horizons can differ. One model may return fewer dates or fields than another. Missing information should remain missing; it is not evidence of no rain, no wind or a temperature of zero.

Use the overlapping dates when making a comparison. A shorter available horizon is not, on its own, a verdict on the model’s accuracy.

Is one forecast model more accurate?

A model comparison gives you another perspective on the same weather question. Broad agreement can make the pattern easier to understand. Disagreement shows that the options are telling different stories about some part of that pattern.

No model is universally best for every place, weather situation and lead time. A finer grid or a familiar name does not automatically settle the question. The app does not turn a comparison into an accuracy score or a guarantee.

When the difference matters, return to the same period later and read the latest available information. For hazardous weather, official local warnings remain a separate source to consult.

Keep the view useful

Choose a consistent starting view: one saved place, one interval and familiar units. Change the model while keeping those choices steady. That makes it easier to understand what changed in the forecast rather than in its presentation.

The Weather Pro overview describes the app’s hourly forecast and widget scope. Radar, minute-by-minute nowcasting and rain push notifications are outside the initial version; switching models does not add those features.