Spring officially begins with the Vernal equinox on March 20th.

The word equinox is derived from the Latin for “equal night” and is used because the days and nights are of nearly equal length.

The Vernal equinox is the point at which the center of the Sun passes over the celestial equator from south to north, signaling the start of the new season in our hemisphere. After the equinox, the Sun will gradually appear higher in the sky, and length of day will grow longer than the length of night. Along with this, the tilt of Earth’s axis as it travels around the Sun causes the change of seasons.

So welcome Spring!

* thanks to the Old Farmer's Almanac for the factoids