Weather forecast models
in windy.app
The weather depends on lots of different factors: wind speed, cloudiness, pressure, humidity, etc. All of them can be measured and represented in meters per second, millimeters of mercury, etc. A mathematical weather model is a combination of all these factors. Such models tend to be very complex, powerful computers calculate them.

Usually weather models are provided by national weather services, but sometimes they can also be produced by groups of enthusiasts.
Predictive models used in Windy.app
ECMWF – Global
A global model by the European Centre for Medium-Range Weather Forecasts. Considered the best for precipitation and cloudiness. Resolution – 14 km. Updates every 12 hours, providing forecasts for 10 days.
GFS27 – Global
The US Global Forecast System, originally created for aviation. Updated 4 times a day, providing forecasts for 10 days.
GFS+ – Global
While the GFS27 interpolates data for every dot within a 27 km x 27 km square, the GFS+ always shows only the maximum result in each square. Updates 4 times a day, forecasting for 10 days.
ICON7, ICON13 – Global
A global model by Deutscher Wetterdienst (German Meteorological Service).
For Europe, higher resolution (7 km) is available for the ICON model, making it even more precise than the ECMWF. The ICON with a 13 km resolution is the global version available worldwide.
— ICON7 – updates 4 times a day, every 6 hours. Provides forecasts for the next 5 days.
— ICON13 – updates 8 times a day, every 3 hours. Provides forecasts for the next 5 days.
NAM – North America
Developed specifically for North America, provides the most precise forecast for the region. Resolution – 12 km. The forecast is updated 2 times a day. Provides forecasts for the next 61 days.
WRF8 – Europe
The WRF is a model for weather forecast calculation developed by several scientific laboratories in different countries.

Using it, Windy.app calculates a hyperlocal forecast for Europe and the Mediterranean. Updates once a day, giving forecasts for the next 3 days.
OpenSkiron – Mediterranean
A local model developed at the University of Athens. Considered one of the best for the Mediterranean. Resolution – 12 km. Updated once a day, providing forecasts for the next 5 days.
OpenWRF – Mediterranean
A local model for the Mediterranean. Based on the WRF technology, adapted by the University of Athens and a group of enthusiasts. Resolution – 12 km. Updated 4 times a day, giving forecasts for the next 4 days.
AROME – France and the surrounding territories
A local model developed by Meteo France (French meteorological service). Covers France and some adjacent regions. Resolution – 1.25 km. It is updated 8 times a day and provides forecasts for the next 42 hours.