Generally speaking, there is a folk custom in leap April, but it doesn't have to be issued at a specific time, as long as it is in March and April of the lunar calendar.

This year is February, and everyone knows that we will send shoes to our parents in leap April, but do you know that we will make "Niangniang cake" for our mother in leap April? Also called "leap moon cakes". In our country, making Niangniang cake for mother in leap year represents health.

In Asia (especially China), leap month refers to one month added every two to three years in the lunar calendar. In order to coordinate the contradiction between the tropic year and the lunar year and prevent the lunar year from being out of touch with the tropic year, that is, the four seasons, 1 leap is set every 2~3 years. In ancient times, there was a leap week, and there were seven leaps in nineteen years. By the time of Linde calendar in Tang Dynasty, the fixed leap week was abolished, and the leap was set in the month without season, so it was leap time.