The same happens at the spring or vernal equinox on the 21st march.
The vernal equinox marks the beginning of spring in the Northern Hemisphere.
"I can't wait to celebrate the Vernal Equinox (the first day of Spring)!"
Vernal Vernal
An example of vernal used in a sentence is this. On March 21st of every year, the vernal equinox marks the first official day of Spring.
vernal: relating to or occurring in the spring
Vernal.
Daylight and darkness are equal during the vernal equinox.
Non vernal
In March; for 2009 it's the 20th at exactly 11:44 AM. The word vernal is derived from the Greek word for spring, but because it only occurs in spring if you live in the northern hemisphere, it is now properly revered to as simply the March Equinox
Equinox (Vernal and Autumnal)
"Vernal" is Latin for "spring".
When will the vernal equinox be in 2010