Slight Cold (Chinese: 小寒), the 23rd solar term, begins this  year on Jan 6 and ends on Jan 20. During Minor Cold, most areas in China have  entered the bitter cold stage of winter. The ground and rivers are frozen. The  cold air from the north moves southward continuously.

Although Slight Cold means less cold than the following solar  term, Great Cold, there is an old saying in China that goes, The days of the  Sanjiu period are the coldest days. Sanjiu period refers to the third  nine-day period (the 19th-27th days) after the day of the Winter Solstice, which  is in Slight Cold. Actually Slight Cold is normally the coldest period of  winter. It is important to keep warm during this period.