When did the dog days of 20 18 start?

The dog days are a special period in the traditional Chinese calendar in China, which is divided into three days: the beginning, the middle and the end. This is the hottest period of the year in China, not three or nine days. The Gregorian calendar time corresponding to the dog days is generally between June and August every year, and the hot weather may last until September. Then let the old calendar tell you when the dog days of 20 18 began.

Q: When did the dog days of 20 18 begin?

A: The dog days of 20 18 begin on July 20 18 17.

Dog days of 20 18: * * 40 days.

July 20 18,17 —— July 26, 2065438+08, the initial period, 10 days.

July 27th, 20 18 —— August 27th, 2065438+08, 15, 20 days.

20 18, 16 August-2065438+25,08, which is the last day, 10 day.

The dog days are calculated according to the lunar calendar, between the middle and late July and the early August of the solar calendar. The time of accommodation is not fixed every year, and the length of accommodation is also different. You need to check the almanac to calculate it. Simply put, we can use the formula of "Xia San Geng" to express the lodging date, that is, from the third Geng day in Xia Hou, the initial lodging is 10 day, the intermediate lodging is 10 day or 20 days, and the final lodging is 10 day.

Starting from the summer solstice, according to the date of trunk, the third Geng day is the first, the fourth Geng day is the middle, and the 1 th Geng day after beginning of autumn is the last. When there are four Geng days between the summer solstice and the beginning of autumn, the middle part is 10 days, and when there are five Geng days, the middle part is 20 days. It can be concluded that the emergence of Geng Day will affect the length of the first half, so there are cases where some years will be 30 days and others will be 40 days.

According to this method, it can be calculated that the dog days of 20 18 are ***40 days.

Reasons for the formation of dog days

After lodging, the surface humidity increases, and the heat absorbed every day is more, but the heat emitted is less, and the heat on the surface is accumulated. So it gets hotter every day, and when it enters the dog days, the accumulated heat on the ground reaches its peak and the weather is the hottest.

In addition, there is much rain in summer, the air humidity is high, and the heat capacity of water is much greater than that of dry air, which is also an important reason for the sultry weather. The subtropical high intensified in July and August. Under the control of the subtropical high, the descending airflow inside the high makes the weather clear and cloudy, which is beneficial to the sunshine, the ground radiation heats up and the weather is hotter.