What are the vernal equinox, summer solstice, autumn equinox and winter solstice?

The spring equinox is around March 2 1, the summer solstice is around June 22, the autumn equinox is around September 23, and the winter solstice is around June 22. The exact time and minutes are not fixed, so you need to check the old almanac.

The vernal equinox on March 20th or March 2nd1day in the solar calendar is when the sun is at 0. At the vernal equinox, the direct point of the sun is on the equator, and the northern and southern hemispheres are equally divided day and night. After that, the direct point of the sun continues to move northward, so the vernal equinox is also called "rising equinox".

The summer solstice is usually on June 2 1-22 of the Gregorian calendar, that is, when the sun runs to 90 degrees of the yellow meridian. On the day of summer solstice, the position where the sun shines directly on the ground reaches the northernmost part of the year, almost directly on the tropic of cancer. At this time, the daylight hours in all parts of the northern hemisphere reach the longest in the whole year.

The autumnal equinox usually falls on September 22-24 of the Gregorian calendar every year. On the autumnal equinox, the sun reaches the longitude 180 (autumnal equinox), almost reaching the equator of the earth, and the whole world is as long as day and night.

From winter to the sun, the solar calendar reaches 270, and festivals are held every year on the Gregorian calendar 65438+February 2 1-23. The winter solstice marks the lowest sun height and the shortest day in the northern hemisphere.