What is the saying that the south wind blows on the solstice in summer?

The saying that the south wind blows on the summer solstice: "On the summer solstice, when the wind leaves, the grains are ripe."

In other words, the south wind blows on the summer solstice, which means that the weather is favorable and crops are easy to harvest. Any wind in the opposite direction to the barrel handle is a headwind, and headwind is an "uncoordinated" wind. The wind is not harmonious and the rain is not smooth.