The vernal equinox of 2007 occurs at 00:07 UTC on March 21, or 20:07/8:07pm my time this evening.
"Vernal" instead of "Spring" because:
- It's okay to use for both hemispheres.
- Also, you could use this term on any other planets on which you should find yourself.
Vernal equinox and autumnal equinox. These names are direct derivatives of Latin (ver = spring, autumnus = autumn), and as such more apt to be found in writings. Although in principle they are subject to the same problem as the spring/autumn names, their use over the centuries has fixed them to the viewpoint of the northern hemisphere. As such the vernal equinox is the equinox where the Sun passes from south to north [across the equator], and is a zeropoint in some celestial coordinate systems. The name of the other equinox is used less often.