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

Equinox: March 21; Summer solstice: June 21; Autumnal Equinox: September 22nd; Winter solstice: 65438+February 2 1.

On the vernal equinox, the sun shines directly on the equator of the earth, and the seasons in the northern and southern hemispheres are just the opposite. The northern hemisphere is the vernal equinox and the southern hemisphere is the autumnal equinox.

On the summer solstice, the direct position of the sun on the ground reaches the northernmost point of the year and almost directly reaches the Tropic of Cancer. At this time, the day in the northern hemisphere is the longest, and the farther north it is, the longer it is.

At the autumnal equinox, the climate in the south begins to enter autumn from this solar term. On this day, the sun reaches the longitude of 180 degrees, and points directly at the equator of the earth, so the day is divided into 24 hours, each 12 hour; There is no extreme day and night phenomenon in the world.

On the winter solstice, the solar meridian reaches 270, and this festival is held on the Gregorian calendar 65438+February 2 1-23 every year. The winter solstice marks the lowest sun height and the shortest day in the northern hemisphere.