Astronomically, spring is defined by the . In the Northern Hemisphere, this usually occurs around March 20 or 21.
The vernal (spring) equinox is the moment when the sun crosses the celestial equator. On this day, day and night are nearly equal in length (about 12 hours each). spring definition season
Meteorologists use fixed dates based on the annual temperature cycle to simplify data comparison. Astronomically, spring is defined by the