What is the meaning of this word in the book "Lunzi Rainfish without food in summer and Lunzi Rainbird without food in winter"?

"Gezhi Yuan Jing" compiled by Chen Yuanlong during the Kangxi period of Qing Dynasty. This passage is quoted as follows:

In spring, rain man has no food, in summer, rain cow has no food, in autumn, rain fish has no food, and in winter, rain bird has no food.

It means:

When it rains in spring, people have no food; when it rains in summer, cows have no grass to eat; when it rains in autumn, fish have nothing to eat; when it rains in winter, birds have nothing to eat.

The specific date of Renzi Day should be calculated according to heavenly stems and earthly branches, which is indicated in the old almanac.