The main difference between a lunar calendar and the Gregorian calendar lies in how they measure and divide time. A lunar calendar is based on the phases of the moon, whereas the Gregorian calendar is a solar calendar that is aligned with the Earth’s orbit around the Sun.
A lunar calendar consists of months that are either 29 or 30 days long, totaling about 354 days in a year. This means that lunar years are approximately 11 days shorter than solar years. As a result, lunar calendars, such as the Islamic calendar, cause the months to drift through the seasons over time.
In contrast, the Gregorian calendar has 12 months with a total of 365 days in a common year and 366 days in a leap year. This system is designed to align more closely with the Earth’s position relative to the Sun, ensuring that seasons remain consistent from year to year.
In summary, the key differences are that lunar calendars are based on the Moon’s cycles, leading to shorter years, while the Gregorian calendar is based on the Sun’s cycles, resulting in a more stable annual structure aligned with the seasons.