What day has 12 hours of daylight and 12 hours of darkness?

Vernal equinox, a date in the spring of the year usually around March 21 and Autumnal equinox, a date in the fall of the year usually around September 23 are the days when earth experiences 12 hours of daylight and 12 hours of darkness.

Further Readings-

1. Difference Between Summer and Winter Solstice
2. Motions of the Earth

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