Why is the weather forecast inaccurate?

Many times the weather is not so easy to predict. It should be said that the current technology has not been able to accurately predict the next few days! But much better than before! The weather forecast of the meteorological station is divided into regions. There are many counties, districts, townships, towns and villages in this area. It is predicted that there will be rain in this area, maybe it will rain in the whole area, maybe it will rain in some places, and it will not rain in some places. So it's not that the weather forecast is inaccurate, but that the area is too large. In addition, climate change is changing rapidly.