Why do different weather forecasting software have different weather forecasts? Don't they buy the weather forecast from the meteorological department but do their own weather analysis?

Every mobile phone manufacturer must have bought the weather forecast data of the meteorological station. Note: here, we only bought data analysis, but we don't have exact values such as degree and rainfall probability. After all the mobile phone manufacturers or weather forecast APP software bought the data, they analyzed the specific degrees themselves, and whether there was an accurate forecast of rain or something. This is what we finally saw. Therefore, different mobile phones and apps are different, because they are all analyzed in their later stages, and the things they buy are only equivalent to semi-finished products. They need to process and analyze themselves before they can show us the finished product.