Zhuge Liang can predict the weather forecast so accurately. Why didn't he predict that it would rain when he caught Sima Yi in Shanggu?

Zhuge Liang is not a god, and the weather cannot be predicted in all cases. The weather is unpredictable.

Later, according to the geographical location of the valley above the Romance of the Three Kingdoms, some experts said that when Zhuge Liang burned the valley above, the water in the valley was evaporated by the flame and rose into the air to meet the original cloud. The water in the cloud became more and more heavy, so it began to rain, and Zhuge Liang's fire-burning plan was solved.

Zhuge Liang's original speculation is correct (it may be cloudy without rain), but the influence of the implementation of the pyrometer is not taken into account: it must be high temperature when burning, and a large amount of water vapor will evaporate in the ancient humid place above when it is high temperature, and a large amount of water vapor will rise into clouds, and a large number of clouds will fall into the rain when it meets. You should know that the valley above is on fire, but it was a big fire. We also feel sorry for Zhuge Liang's plan, but the weather is one of the most changeable things. The current weather forecast is high in science and technology, with an accuracy rate of about 50%.