On what date does the vernal equinox occur?

The vernal equinox occurs on March 21, which marks the beginning of spring in the Northern Hemisphere. This date is significant because it is when the sun crosses the celestial equator, resulting in nearly equal day and night lengths across the globe. The equinoxes, which occur in March and September, are key astronomical events that signal a change in seasons due to the tilt of the Earth's axis and its orbit around the sun. Understanding this event is essential in Earth science as it relates to the Earth's movement, seasonal changes, and climate variations. The other dates listed do not align with the astronomical definition of the vernal equinox and are not recognized as significant markers in the seasonal calendar.