Anciently, the frost is divided into three seasons: "First, the jackal is a sacrificial animal; second, the grass and trees are yellow and fall; third, the stinging insects are salty and swooping."

It means that animals like jackals start to reserve food for winter from the frost; the grass and trees are yellowing and leaves are falling all over the ground; and animals that are ready to hibernate start to hide in their burrows for the winter.