Dongzhi, or Winter Solstice, is one of the most significant solar terms in the Chinese calendar. It occurs annually between December 21 and 23, when the sun reaches 270 degree longitude. During this time, the Northern Hemisphere experiences the shortest day and the longest night of the year. Known as the "Winter Festival" or "Minor New Year" in ancient times, Dongzhi carries profound cultural and historical significance.

• Onset of Severe Cold: Dongzhi marks the start of the "Nine-Nine Cold Days," the chilliest period of the year.

-Health Advice: Focus on nourishing the kidneys and preserving yang energy by consuming black foods like black sesame and black beans. Keep the feet warm to avoid illness.

-Agricultural Activities: In southern agricultural areas, Dongzhi is a crucial time for planting wheat and rapeseed, as well as maintaining irrigation and frost protection.