In the Northern Hemisphere spring officially
begins on this Saturday, the vernal equinox, three days from today.
Soon trees will bud, snows will melt, and for the next six months
daylight will tick more minutes off the clock than darkness.
The reverse is true in the Southern Hemisphere.
But whether you are entering the season of light or darkness,
don't be fooled into thinking that on the equinox the length of
the day is exactly equal to the length of the night. It's not.
The day of light and dark equality always
happens before the spring and after the fall equinoxes, according
a public affairs specialist with the U.S. Naval Observatory in
"Exactly when it happens depends on where
you are located on the surface of the Earth," he said. For example,
in Washington, D.C., sunrise and sunset were exactly 12 hours
apart on March 16. Solar balance occurred in Bogotá, Colombia,
on February 24.
By the time
the center of the sun passes over Earth's Equator—the official
definition of equinox—the day will be slightly longer than the
night everywhere on Earth. The difference is a matter of geometry,
atmosphere, and language.