Why is the weather forecast on QQ inaccurate?

Because making weather forecast needs to deal with a lot of data. The previous computer was slow, and the calculation took 15 days. Today's computers have advanced to three days (or even less) to calculate data. In other words, the weather forecast made today uses the data collected three days ago, so there is a certain error. Making weather forecast needs to process a lot of data, although the computer is very advanced now.