Why did Zhuge Liang pretend to borrow the east wind? Did he just say that he would watch the weather forecast?

A: Because this passage is fictional in Romance, it was specially compiled to deify Zhuge Liang.

If you find it hard to accept the fact, let me rephrase the answer: because in those days, some people believed that they would borrow the east wind, and no one believed that they would look at the weather. In addition, in case of failure, you can borrow the east wind to throw the pot to the fairy, and you can only pay for your own beheading according to the weather.