The summer solstice in 2020 is June 21, counting from this day, the date of the appearance of the third gengzhi is July 16, so this year into the ambush is this day.

The three ambrosia days are divided into the first, middle and last ambrosia, the first and last ambrosia are 10 days respectively, and the middle ambrosia is 10 days or 20 days in two cases. It was just mentioned that the first ambush starts on the third g day after the summer solstice and ends on the day before the fourth g day after the summer solstice. This year, the first ambush started on July 16th and ended on July 25th.

The end of the ambush is counted from the first g day after the beginning of autumn, this year, the beginning of the autumn festival is August 7, the first g day is August 15, so the end of the ambush is the beginning of August 15, to August 24, the end of the entire three ambush days.

The reason why the middle ambush has both 10 and 20 days is because the time of the year is a period of 365 days, but a geng day occurs every 10 days, and 365 days will not be a multiple of 10, so the geng day occurs at an irregular time. People have concluded that if there are four Geng days between the summer solstice and the beginning of autumn, the mid-volt is a 10-day period, and if there are five Geng days, the mid-volt will be 20 days.

Expanded

Note:

1, excessive sun exposure, ultraviolet rays will destroy collagen, elastic fibers, so that the skin premature aging, and even cause skin cancer. Strong sunlight will also damage the eyes. In addition, 10 a.m. to 2 p.m. UV is the strongest, this time to pay special attention to sunscreen.

2, air conditioning one of the main causes of disease, is too large a temperature difference between indoor and outdoor. Although the human body has a certain ability to regulate body temperature, but this ability has a limit. The temperature difference between indoor and outdoor should not be too large, generally around 8 ℃ -10 ℃. In summer, although there may be a high temperature of 38 ℃ or more, but most of the day the temperature is below 35 ℃, so the indoor temperature of about 26 ℃ is more appropriate.