May I ask why the half of July is on July 13 and not July 15?

In fact, the half of July is from July 12 to July 15, not only July 15 day

Every year on the 15th day of the seventh month of the lunar calendar is China's Mid-Yuan Festival, the festival and other festivals compared to some of the horror of the color, because in folklore people also called the Mid-Yuan Festival is the Ghosts Festival. Zhongyuan Festival is also known as the Ghost Festival, half of the seventh month, a few areas also called the Day of the Dead. It is one of the three ancient festivals, the first month of the 15th on the Yuan Festival, celebrating the first month of the Lantern Festival. July 15 in the Yuan Festival, ancestor worship.

Mid-Yuan Festival in folklore commonly known as the "Ghost Festival", also known as the "July Festival", "half of July", and New Year's Eve, Qingming Festival, Chung Yeung Festival (in addition to, Qing, nine) and other three festivals, and Known as China's traditional festivals in the ancestors of the four major festivals Zhongyuan Festival is not only famous in the folk, more Buddhist, Taoist two important. In Buddhism, it is also known as the "Bon Festival". Legend has it that after death, some people are elevated to heavenly deities, while others become ghosts, and the main basis for this is whether or not the person in question has merit