What is the introduction and origin of slight cold solar terms? What's the difference between the north and the south during the slight cold?

Slight cold is the penultimate solar term among the 24 solar terms. Literally, slight cold and severe cold should be severe cold, but according to records, most of them are relatively cold. So what is the introduction and origin of the slight cold solar terms? What's the difference between the north and the south during the slight cold? What is the introduction and origin of slight cold solar terms?

Slight cold difference between north and south