The conversion rules for forecasting the climate and harvest of the year are extremely complicated. A brief example is as follows: The relative positions of the spring cow and mangshen represent the order of the Spring Festival and lichun in that year. For example, if lichun is before the Chinese New Year, the god will stand behind the cow.

The god has different appearances such as a child, young adult, or old man based on his age, calculated on Heavenly Stems and Earthly Branches, a complex calendrical system which was created to codify the patterns of life and of the universe itself.

Since the general climate and the five elements are different from year to year, theoretically, the shape of the spring cow map should be different every year.

However, the calculation is not a field of knowledge in which everyone is well versed, so average folks have their own simplified cognitive pattern: Mangshen's clothing thus invites room for interpretation. If he wears a bamboo hat, it indicates that the weather will be hot that year; if he wears shoes and his robe covers his ankles, it will be relatively dry.