Chinese Calendar Has Leap Months
The name of a leap month is the same as the previous lunar month. The leap month’s place in the Chinese calendar varies.
When Is the Leap Month?
Approximately every three years (7 times in 19 years), a leap month is added to the Chinese calendar. To determine when, find the number of new moons between the 11th month in one year and the 11th month in the following year.
A leap month is inserted if there are 13 New Moons from the start of the 11th month in the first year to the start of the 11th month in the next year.
The Chinese calendar uses a solar term system that has 12 principal terms to indicate when the Sun's longitudes is a multiple of 30 degrees. Unlike all other months, the leap month does not contain a principal term (Zhongqi).