What time is the middle of winter?

the dead of winter is between three or nine days and five or nine days. That is between January and February.

In the "March 9th" period, because the ground receives less solar heat, the heat dissipation at night exceeds the heat absorbed during the day. At this time, the heat stored on the ground has been exhausted, and the ground temperature has gradually dropped and the weather is getting colder and colder because the heat cannot make ends meet. At this time, if there is the influence of cold air, the weather will become very cold. Therefore, the "March 9" weather is the coldest. The middle of winter means that the ice is long and the snow is several feet deep.

coldest weather:

As a method to record the cold winter, China folks divide the 81 days after the winter solstice into 9 stages, each of which is 9 days, which is called "Winter 99", which is often called "Nine Days in Winter". Among them, the 19th to 27th day after the winter solstice every year is called "Sanjiu".

In a year, the winter solstice has the shortest day, the smallest angle between the sun's rays and the ground, and the ground gets the least amount of solar heat. It should be said that it is coldest on the winter solstice, but the fact is not, but it is "cold on March 9th". Why is this?

meteorologists say that the temperature on the ground is not only affected by the intensity of solar radiation, but also related to ground heat dissipation. Since the days are long and the nights are short after the summer solstice, the angle between the sun rays and the ground is large, and the ground gets the most heat, and there is less heat dissipation at night, so the heat storage on the ground gradually increases. By the winter solstice, although the sun irradiation time is short and the angle between the sun rays and the ground is the smallest, the heat stored on the ground in summer and autumn can be supplemented, so the weather is not necessarily very cold. Deep winter is the meaning of ice.

Precautions for three or nine days

1. Mental health should be peaceful

In winter, natural stinging insects lurk in hiding, and use hibernation to recharge their batteries, so as to prepare for the vitality of next spring. At this time, the metabolism of human body is also in a relatively slow period. Therefore, keeping in good health in winter should focus on "hiding". "Hiding" means that people should keep quiet in winter.

In winter, it gets dark early and the light time is short, which is also a reason that people are prone to depression. When night comes, the secretion of melatonin in the pineal gland of human brain is enhanced, which can affect people's mood, while light can inhibit the secretion of this hormone and keep people in a good mood.

2. Keeping in good health in daily life emphasizes cold protection

Chinese medicine believes that after winter, it is an important aspect of keeping in good health. That is to say, people should go to bed early and get up late in the cold winter. Going to bed early can nourish the human body's yang, and it is best to get up after the sun comes out. At this time, the human body's yang rises rapidly, and the content of adrenocortical hormone in the blood also rises gradually. At this time, getting up is clear-headed and witty. However, it may be difficult for office workers to get up late, so we should try to go to bed early and not stay up late.

3. The room temperature should be kept constant

If the room temperature is too low and people feel cold, it is easy to hurt the human body. If the temperature is too high, the temperature difference between indoor and outdoor is large, and it is easy to get cold when going out. Therefore, the room temperature should be kept between 18 degrees Celsius and 22 degrees Celsius. However, doors and windows should not be closed, and windows should be opened for ventilation to keep indoor air flowing.

4. Pay attention to the maintenance of the back

Chinese medicine believes that the back is the main part of the bladder meridian of the foot sun in the human body. The bladder meridian of Foot Taiyang has the function of preventing the invasion of exogenous pathogens. Once a person suffers from cold, it will damage the yang, resulting in upper respiratory tract infection or recurrence and aggravation of old diseases. For the elderly, children and people with gastric and duodenal ulcers and cardiovascular and cerebrovascular diseases, it is particularly important to warm their backs. It is best for these people to wear a close-fitting cotton vest after beginning of winter.

5. Pay attention to keeping your feet warm

"Cold starts from your feet". Feet are the farthest part of the human body, with thin fat and poor warmth retention. Traditional Chinese medicine believes that plantar acupoints are closely related to human internal organs. If the foot catches cold, it can cause colds, abdominal pain, lumbago and leg pain, dysmenorrhea and other diseases. Keep your feet warm. First, wear shoes to prevent them from being too tight, too loose and too thin. Second, use cotton socks as socks. Second, move your feet more at ordinary times to promote local blood circulation. Third, soak your feet with warm water every night before going to bed. The water temperature is 5-6 degrees Celsius, which can eliminate fatigue, keep out cold and prevent freezing, and promote sleep.