农历, also known as the lunar calendar, is a calendar system based on the phases of the moon. It consists of 12 months, with each month beginning on the new moon. Because the lunar year is shorter than the solar year, an extra month is added approximately every three years to keep the calendar in sync with the seasons. In China, the 农历 is used to determine important festivals, such as 春节 (Spring Festival) and 中秋节 (Mid-Autumn Festival). It plays a significant role in traditional customs, agriculture, and astrology, influencing various aspects of daily life and cultural practices.