When is the vernal equinox? When is the vernal equinox of the sun?

The vernal equinox is the midpoint of 90 days in spring. One of the 24 solar terms, around March 20 of the Gregorian calendar every year, when the sun is located at 0 (vernal equinox) of the yellow meridian. On the vernal equinox, the sun shines directly at the equator of the earth, and the seasons in the northern and southern hemispheres are opposite. The northern hemisphere is the vernal equinox and the southern hemisphere is the autumnal equinox. The vernal equinox is a new year in Iran, Turkey, Afghanistan, Uzbekistan and other countries, with a history of 3,000 years.