What are the signs of rain and snow?

When it snows heavily, the cows should stop.

This proverb means that if it snows heavily in the rainy season, it means that the weather is very cold, the temperature is very low, the land has not been thawed, the farmers' spring ploughing has not started, and the cows have to rest.

The rainy season is the second of the 24 solar terms. After the rainy season, spring comes back to thaw, and farmers are preparing for spring ploughing.

If the cold air activity is intense at this time and the warm and humid airflow is restrained, it will rain or snow. It's getting cold and farmers can't work in the fields. The cows in the cultivated land had to rest at home.