Why is the weather forecast in Nanjing always inaccurate?

Recently, the weather in Nanjing is changeable, and the accuracy of the forecast is almost the same. In addition, when the rainy season comes, it rains for a while and it doesn't rain for a while. Seeing that dark clouds are gathering, it is difficult for the gods to predict whether it will rain or thunder. As the saying goes, the weather is unpredictable and people are unpredictable.