The vernal equinox occurs around March 20 or 21 each year, marking the beginning of spring in the Northern Hemisphere. On this day, the sun crosses the celestial equator, resulting in nearly equal amounts of daylight and darkness. This event is significant in many cultures, often celebrated as a time of renewal and growth. During the vernal equinox, the tilt of the Earth's axis is such that the sun shines directly on the equator. This phenomenon affects weather patterns and is a key factor in the changing seasons. The equinox is also associated with various festivals, such as Ostara in pagan traditions and Nowruz, the Persian New Year.