During equinox, all places across the globe experience equal lengths of day and night. This is because during the equinox, the plane of the Earth's equator passes through the center of the Sun, which causes the Sun to be directly above the equator. As a result, the daylight and darkness hours are approximately equal in duration all over the world, regardless of latitude. This happens twice a year, around March 20th-21st and September 22nd-23rd, and marks the change of seasons from winter to spring, and from summer to autumn, respectively.