@worf1001 Again, weather model data is provided along a grid of points. [image: 1687174539489-f6dc3918-186e-4efd-8fcc-cb28d0310ebd.jpeg] Basically the distance between grid points is the model resolution (like resolution of a photo). In general case, your location is between grid points. How to calculate the temperature at your location? You can take the temperature of the nearest point. Here 23°C. Or you take the distance-weighted average of the temperatures at the 4 points (interpolation). [image: 1687175742298-9ae322a3-b793-44da-b089-7ebfda091c9d.jpeg] You may understand that the result is not the same. Windy makes interpolation. Meteoblue in the Multimodel uses the nearest point as far as I know. Please contact Meteoblue to confirm since you consider them as the Reference.

@worf1001 The map showing the precipitation over the last 3 hours is probably based on this parameter: https://codes.ecmwf.int/grib/param-db/?id=228223 In Basic panel, hourly precipitation amounts are actually the total of large-scale rain, convective rain, and snow which are shown in detail in Meteogram. They therefore come from different parameters. You will have fun finding which ones by typing “precipitation” in the search box : https://codes.ecmwf.int/grib/param-db/ As a conclusion to this long discussion, remember that weather forecast relies more on probability rather than arithmetic.