Is there a saying like dog days in the twenty-four solar terms?

The specific meaning of the twenty-four solar terms

The solar terms 1 and 24 ("fixed air method" solar terms) reflect the annual apparent motion of the sun, so their dates are relatively fixed in the Gregorian calendar. The solar term in the first half of the year is on the 6th, the solar term in the second half is on the 8th and the solar term is on the 23rd, with a difference of 1 ~ 2 days.

2. The earth revolves around the sun once every 365 days at 6: 09 and 10 seconds (exactly) and rotates once every 24 hours. Because the orbital plane of the earth's rotation is not the same as the equatorial plane, but maintains a certain inclination angle, the position of direct sunlight on the earth is different all year round. In the northern hemisphere, the sun shines directly on the Tropic of Cancer (23 26' north latitude), which is called summer solstice in astronomy. When the sun shines directly on the tropic of Capricorn (23 26' south latitude), it is called the winter solstice; The solstice in summer and the solstice in winter mean that it is halfway between summer and winter.

There are two times in a year when the sun shines directly on the equator, that is, the vernal equinox and the autumnal equinox, which are in the middle of spring and autumn. The day is as long as the night. The activity law of the direct solar point is: vernal equinox (March 2 1 or so), the direct solar point is at equator 0, and then moves northward. During the summer solstice (around June 22nd), the direct point of the sun is on the Tropic of Cancer (23 26' N), and then moves south.

4. At the autumnal equinox (around September 23rd), the direct point of the sun is 0 on the equator, and then it continues to move southward. During the winter solstice (around 65438+February 22nd), the direct point of the sun is on the tropic of Capricorn (23 26), and then moves northward.