There are seven big months in a year, which are calculated according to the solar calendar, not the lunar calendar.

There is a poem that remembers the big and small moons:

One, three, five, seven and eighty years old

Thirty-one days will definitely be good

The rest are thirty days

Only February 28th

This is mainly for the convenience of distinguishing and remembering the big and small months. The wax in the first sentence represents December. If you look at it this way, there are seven big months and five small months. It should be said that there are seven months for the big month and five months for the small month.