"The summer solstice three Geng number heads", on the 21st, the summer solstice. Astronomical experts said that as in the previous year, this year's dog days are also 40 days.
The summer solstice is not only the longest day in the Northern Hemisphere and the shortest day at night, but also determines the length of the sky.
According to the traditional method of extrapolation, the third G-day after the summer solstice is called “preliminary voltâ€, and from the fourth G-day after the summer solstice, it is “mean voltâ€, and the first G-day after the beginning of the fall is “end-of-sightâ€. It is called "three volts".
"Because the change of G-Day is uncertain, the date of annual incarnation varies from year to year." Zhao Zhiyu, an astronomy education expert and member of the Tianjin Astronomical Society, said that both the initial and last days were 10 days, and the number of days in the middle was not fixed. When there are 4 G-days between the summer solstice and Liqiu, the medium volt is 10 days; when there are 5 G-days, the mid-volt is 20 days. The number of days in the first, middle, and last days adds up to the total number of days in the sky. “There are five G-Days in the autumn solstice to Liqiu this year, so this year’s mid-day is 20 days.â€
Specific to this year's "three days", on July 17 to pay "the first volt", on July 27 to pay "zhongfu", on August 16 to pay "end", August 26 "extended."
Meteorological data show that the hot and cold weather is not determined by the duration, but is determined by the atmospheric circulation background, the location, intensity of the subtropical high, and the time of control.
“Because of the high temperature, strong solar radiation, and high humidity in the air, people will feel the weather is hot and unbearable. It is the hottest time of the year.†Zhao Zhijun said, “At this time, the public must pay special attention to the cooling of the heatstroke and timely water supply. Minimize unnecessary trips."
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