Here's why:
* Spring is an astronomical event, not a scientific one. It's defined by the position of the Earth in its orbit around the sun, specifically when the sun is directly over the equator.
* The first day of spring varies by calendar. It's either the vernal equinox (around March 20th or 21st in the Northern Hemisphere) or a date that falls within a specific range, like in the Chinese lunisolar calendar.
While there's no scientific name, here are some related terms:
* Vernal equinox: This is the astronomical event that marks the beginning of spring in the Northern Hemisphere.
* Spring equinox: This is the name for the vernal equinox in the Northern Hemisphere and the autumnal equinox in the Southern Hemisphere.
* Equinox: This refers to the two days in a year when the sun is directly over the equator, resulting in approximately equal lengths of day and night.
