Rain is the second of the 24 solar terms. At this time, the temperature rose, the ice and snow melted, and the precipitation increased, so it was named rain. "In the middle of the first month, there is water in the sky as soon as possible. Spring belongs to the wood, but the wood must be water, so the beginning of spring is followed by rain. And when the east wind is thawed, it is scattered and becomes rain." It means that before and after the rain solar term, everything starts to sprout and spring is coming.