040715 AUGUSTA: A patron checks out a Dogwood tree beside the second fairway during the Masters at Augusta National Golf Club on Tuesday, April 7, 2015, in Augusta, Georgia. Curtis Compton / The Atlanta Journal-Constitution
2. What does equinox mean? The Earth spins on a tilted axis, which means its northern and southern hemispheres trade places in receiving more light as it orbits the sun. The axis is not inclined toward or away from the sun at the equinox, which is derived from the Latin words for equal (aequus) and night (nox).
3. Why is it important? For ancient societies, the vernal and autumnal equinoxes marked when winter turned to spring and when summer turned to fall, respectively, and helped people track time-sensitive things, such as when to plant crops.
4.Didn’t spring start already? Meteorological spring started March 1. Forecasters like to start the season on the first day of March because they prefer a calendar in which each season starts on the same day every year. It helps with record keeping, among other reasons. But the Earth, sun and stars don’t quite conform to the Gregorian calendar – thus the vernal equinox doesn’t fall on the same day every year.
5. What's next? The summer solstice is June 21, but meteorological summer begins a few weeks earlier on June 1.
– The Cox Media Group National Content Desk contributed to this report.