If it is calculated according to the lunar calendar that has been used in China, the animal sign should be calculated in beginning of spring.
It's just that with the loss of traditional culture, many people use New Year's Day in the solar calendar or the first day of the first month in the lunar calendar to distinguish their zodiac signs, which is incorrect.
According to historical records, the method of taking beginning of spring as the standard of the zodiac began in the Shang and Zhou Dynasties. At present, folklore such as the yellow calendar, traditional numerology and divination all take beginning of spring as the basis for calculating the zodiac.
For example, beginning of spring in 217 is the seventh day of the first month, so people born before the seventh day of the first month should not belong to chickens, but to monkeys. People born after the seventh day of the first month in 217 and before beginning of spring in 218 should be counted as monkeys. This is because, in ancient China, heavenly stems and earthly branches was used to record the year, month and day, and the twelve zodiac signs corresponded to the twelve branches, for example, the ugly son corresponds to the rat, the ugly son is the year of the rat, the ugly year is the year of the ox, the year of the tiger and the year of the rabbit. Because the chronology of the dry branch is based on the sun, and the alternation of heavenly stems and earthly branches begins in beginning of spring every year, the demarcation line of the dry branch year is beginning of spring, and the Lunar New Year begins in beginning of spring.