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

Vernal equinox: the fourth of the 24 solar terms, March 20th or 21; Mid-spring, the length of day and night is equal.

Summer solstice: the tenth of the 24 solar terms, June 2 1 or 22; It means that the heat is coming, with the longest day and the shortest night.

Autumnal equinox: the sixteenth day of the twenty-four solar terms, September 23rd or 24th; It means that in the crisp autumn, day and night are equal.

Winter solstice: the 22nd solar term in 24 solar terms, which falls on 65438+February 20th or 22nd, 265438+; It means that winter is coming, with the shortest day and the longest night.

All the above are Gregorian calendar.