In 2016, UNESCO list the Twenty-Four Solar Terms/ 24节气 as the Intangible Cultural Heritage of Humanity. 

Farmers in ancient China,  through observation of the annual motion of the sun,divided a year into 24 equal segments; each segment was called a “ 节气jie qi” or solar term. Hence the 24 segments are collectively called the 24 Solar Terms. Each season has 6 solar terms. This calendar serves as a precise time frame for farming practice, production, festivals for farmers. It preserves ancient knowledge and perception of the regularity of seasons, of astronomical laws and of other local natural phenomena occurring in the course of the year. It's also called the China's fifth great invention. 

The 1st Solar Term is called "立春" (lì chūn, Spring Commences), which usually falls on the 3rd - 5th of February. "立" means, establishing,  the beginning of all things on earth. It thus suggests it's the start of Spring. For Summer Commences, it's called 立夏Lìxià, Autumn Commences, 立秋Lìqiū, winter commences 立冬Lìdōng。 

 "雨水" (yú shuǐ, Spring Shower) starts on 18th - 20th of February , ends around 5th of March, implies that snow is disappearing, more raining is coming. 

春雨贵如油Chūnyǔ guì rú yóu，it means Spring rain is as precious as oil. It's great for preparing the earth for Spring farming.

一日之际在于晨 Yī rì zhī jì zàiyú chén， 

The whole day's work depends on the good planning in the early morning,

一年之际在于春  yī nián zhī jì zàiyú chūn

The whole year's work depends on the good planning in Spring. 

❀❀ Recommended reading: Theme-based Chinese Learning and Topic focused vocabularies