That's also reflected in Google's Doodles for the day. Much of the northern hemisphere gets a Doodle celebrating Spring (above, top, from the Canadian Google homepage), while much of the southern hemisphere gets a Google Doodle celebrating Fall (above, bottom, from the Chilean Google homepage).
To mark the coming of spring and autumn, today’s Google Doodle was designed by Finnish clothing design company Marimekko. Marimekko is known for its bold, colorful prints. We'd admit, though, if we didn't know we were looking for the word "Google," we'd have trouble finding it.
An equinox is one of two times during the year when the length of day and the length of night are approximately equal, and the vernal equinox marks the end of winter and the beginning of spring in the northern hemisphere.
The exact date of that doesn't always match up with the equinox, though, as location has a lot to do with it. For example, the date when Washington, D.C. had a day with equal daylight and night hours was actually March 16.
If you're in the N.H., Happy Spring. If you're in the S.H., Happy Autumn.
Google posted a video about the Doodle; you can see it below.