Lunar or Solar—Why the Chinese and Western Calendars Differ So Greatly

As we've just celebrated the Moon Festival (also known as Mid-Autumn Festival), you probably want to know how to calculate the day it falls on as it appears on a different day of the calendar every year.

The exact day is the 15th day of the 8th month on the Chinese lunar calendar, which is very different than the Western calendar.

The Western calendar, formally known as the Gregorian calendar, is a solar calendar. It counts the time it takes for the Earth to go around the Sun once as a year. Each month has the same number of days every year, except during leap years.

The Chinese lunar calendar is, despite its name, a lunisolar calendar. It counts the length of time it takes for the moon to go around the Earth as a month, while still counting the time it takes for the earth to go around the Sun as one year. The outcome is the Chinese lunar calendar having a variable amount of days every year, sometimes even including an extra month!  

So now you understand why traditional Chinese holidays like Chinese New Year, Lantern Festival, and, of course, Moon Festival seem to fall on different days every year on the Western calendar.