What do you mean, the big wild goose flies north to warm the swallow south, and the gas turns cold?

It means that the weather will get warmer when you see the geese flying north, and it will get colder when you see the swallows flying south, so winter is not far away.

Goose and swallow are both migratory birds. When spring comes, winter comes, everything recovers and is warm, the geese will return to the north. Autumn is coming, the weather is getting colder and colder, and swallows fly back to the south.

This is a weather proverb.

Extended data:

Characteristics of weather proverbs

First, these proverbs are the crystallization of thousands of years of agricultural production experience, so many of them can coincide with modern meteorological theory. However, due to the limitation of production conditions and knowledge level at that time, most of these proverbs are an experience of knowing what they know but not knowing why, which cannot rise to the level of scientific theory.

Secondly, because these proverbs are the products of agricultural society, there are great local restrictions. A proverb is very useful in the north, while people who are proud of things in the south have a narrow vision and limited experience, so they can't observe and analyze problems from a comprehensive perspective.

Third, it also includes the far-fetched attachment of feudal superstition and idealism, but if we can study it with historical materialism and dialectical materialism, it is not difficult to extract the essence from roughness and discover the wisdom of our ancestors.

Baidu encyclopedia-weather proverb