What is the first sentence of the weather proverb "Rain"?

Laoyun picks up the car (it rains if it doesn't rain), and some people say that Laoyun picks up the car (it rains). That is to say, when the sun is about to set, the clouds that greet the sun are gloomy, and the older generation calls this' old cloud'.

It is an old meteorological proverb that Lao Yun gets off when he drives. This proverb, which is not very accurate, is a summary of the old man's experience and just a guess. Weather reference for traveling or doing things the next day.