Every year around January 20, when the sun reaches 300° of the yellow meridian, it is "Dahan", which means the weather is cold to the extreme. Dahan is the last of the twenty-four solar terms, and although the weather is cold at this time, it is close to spring, so it is not as cold as it was during the Little Cold.

As with the Little Cold, the Big Cold is also a festival that indicates the degree of cold weather. Recent meteorological observations show that, in some parts of China, the cold is not as cold as the small cold, but, in some years and a few places along the coast, the lowest temperature of the year will still appear in the cold season, while the small cold, cold season is also the least rainy period of the year.

The cold is the whole year, but also the last of the winter season, this time the weather is still in the coldest time period, but because the winter is coming to an end, can be vaguely felt in the earth back to the signs of spring, is a year of "transport", "gas

The diet of the Great Cold should abide by the principle of preserving yin and submerging yang. Diet should reduce salty and increase bitter to nourish the heart gas, so that the kidney qi solid, avoid sticky hard, cold food, hot food, to prevent damage to the spleen and stomach yang qi, but hot and dry things can not be over-eaten. The flavor of the food can be appropriately strong, and there should be a certain amount of lipids to maintain a certain amount of heat. In addition, more yellow-green vegetables should be consumed, such as carrots, greens and spinach. In addition, due to the cold coincides with the Spring Festival, the general family will prepare a wealth of New Year's food, at this time to pay attention to avoid hunger and satiety disorders, at the same time, you can eat more with the spleen stagnation effect of food, such as Huaishan, hawthorn, pomelo, etc., but also more to drink, such as millet congee, spleen porridge, dampness congee and so on for conditioning.

On the other hand, the cold season is still a good time to winter tonic, the focus should be placed on the solid protection of the spleen and kidneys, nourishing the liver and blood, tonic method has two: one is food tonic, the second is medicine tonic. "Medicine is not as good as food", should be based on dietary supplements. People who favor Yang deficiency dietary supplement to warm food is appropriate, such as mutton, chicken, etc.; favor Yin deficiency to nourish Yin food is appropriate, such as duck, goose, turtle, turtle, fungus, etc.. Medicinal supplements should be taken in combination with one's physique and symptoms, such as weak physique, qi deficiency people can take ginseng soup. People who can drink alcohol can also be combined with medicinal wine tonic, common ten full tonic wine, Chinese wolfberry wine, Cordyceps tonic wine and so on.