Which Chinese festival falls on the winter solstice?

The Chinese festival that falls on the winter solstice is the Dongzhi Festival.

Dongzhi is both the name of the 22nd solar term in the traditional Chinese calendar and the festival associated with it. The term begins when the Sun reaches 270° celestial longitude, usually on December 21–23 in the Gregorian calendar.

The festival has roots in ancient Chinese ideas of yin-yang balance: after the year's shortest day, daylight gradually increases and yang energy is thought to return. Historically, families honored ancestors and gathered for seasonal meals.

Customs vary by region. In northern China, dumplings are traditional, while southern communities commonly prepare tangyuan, round glutinous-rice balls associated with reunion. Dongzhi is not the same as Qingming, the spring ancestor-remembrance festival, or the Mid-Autumn Festival.