Three dog days is the hottest day of the year, and it is also a good opportunity to cure winter sickness in summer. Do you know when the dog days are hottest? When do they start? Let's get to know.
When does the dog days in 2018 start? The dog days in 2018 start on July 17, 2018.
Dog days in 2018: 40 days in total
July 17, 2018 - July 26, 2018, the first fall, 10 days
July 27, 2018 - August 15, 2018, zhongv, 20 days
August 16-25, 2018, last 10 days
The three volts are calculated according to the lunar calendar, which is between the second half of July and the first half of August. The time of ambush is not fixed every year, and the length of the ambush is not the same. It needs to be calculated by checking the almanac. It can simply use the four word formula 'summer solstice three Geng' to express the date of ambush, that is, from the third 'Geng' day after the summer solstice, the first ambush is 10 days, the middle ambush is 10 days or 20 days, and the last ambush is 10 days.
From the beginning of the summer solstice, according to the arrangement of the days of the GaN and Zhi dynasties, the third day of Geng is the first day of ambush, the fourth day of Geng is the middle day of ambush, and the first day of Geng after the beginning of autumn is the last day of ambush. When there are 4 g days between the summer solstice and the beginning of autumn, the median period is 10 days, and 5 g days is 20 days. From this, it can be concluded that the occurrence of the day of Geng will affect the length of the middle volt, so there are some years with 30 days of dog days and some years with 40 days of dog days.
According to this method, the total number of dog days in 2018 is 40 days.
The reason for the formation of the "three dog days" is that the surface humidity becomes larger, the heat absorbed is more, the heat emitted is less, and the heat of the surface layer accumulates, so it gets hotter day by day and enters the "three dog days". The accumulated heat of the ground area reaches the highest peak, and the weather is the hottest.
In addition, there is more rain in summer, and the air humidity is large. The heat capacity of water is much larger than that of dry air, which is also an important reason for the sultry weather. In July and August, the subtropical high was strengthened. Under the control of the subtropical high, the downdraft inside the high pressure made the weather clear and cloudless, which was conducive to the sunshine, the ground radiation increased temperature, and the weather was even hotter.
Which is the hottest day?
The hottest stage of three dog days: Zhongfu
1. When it comes to which one of the three volt days is the hottest, we need to mention the folk saying "cold in Sanjiu, hot in Zhongfu", which means that the hottest day of the year belongs to the "three volt", and the "three volt" is the hottest. After the end of the day, the weather began to cool.
2. First of all, as the surface humidity increases after the fall, the heat absorbed by the ground every day is more, the heat emitted is less, and the heat of the surface layer accumulates, so it gets hotter day by day. Entering the middle voltage, the heat accumulated on the ground reaches the highest value, and the weather is the hottest.
3. In addition, there is more rain in summer, and the air humidity is large. The heat capacity of water is much larger than that of dry air, which is also an important reason for the sultry weather in three rainy days.
4. In July and August, the subtropical high pressure was strengthened. Under the control of the subtropical high, the downdraft inside the high pressure made the weather clear and cloudless, which was conducive to the sunshine, the ground radiation increased temperature, and the weather was even hotter.
5. After entering the final days, the weather is gradually cool. It's cooler in the morning and evening. It's still hot at noon. Each area will be different. Because the last fall is after the beginning of autumn, even the so-called "autumn tiger" is hot in the daytime and cool in the morning and evening.
How to determine the date of Sanfu?
First fall, according to China's calendar law, this is the beginning of a real summer day. The people often say: heat in three volts, cold in three nineties. The three dog days are the season with the highest temperature and humidity in a year, which are divided into the first, the middle and the last, in which the first and the last are fixed for 10 days, some are 10 days, some are 20 days.
At the beginning of the incubation period, it is called in or out, and at the end of the incubation period, it is called out. The number of medium voltage days depends on the time of lodging. Generally, the number of days of lodging before July 28 is 20 days, the number of days of lodging on July 29 is 10 days.