Moonlady Holiday Compilation:
In 2013, on March 20 at 11:02 Universal Time, or 6:02 a.m. Central Daylight Time for us in the central U.S., the Sun will cross directly over the Earth’s equator. This moment is known as the vernal equinox in the Northern Hemisphere. For the Southern Hemisphere, this is the moment of the autumnal equinox.
Spring Equinox overview
video of seasons caused by axial tilt and Earth orbit