In rural areas, there is a proverb, "It rains over Sanqiu". What does this mean?

In the countryside, there is a saying? Is it raining in Sanqiu? This usually means that the weather is getting cold. There are four seasons in a year, one in March, and autumn refers to July, August and September of the lunar calendar. The rain in spring and summer itself is cool, but it will increase the cold in autumn, so the rain over Sanqiu mostly means that the weather is getting colder and colder, and winter is coming.