The equinox is when the sun's direct rays are right on the equator
CHICAGO (WLS) -- The clouds got in the way of the semi-annual phenomenon known as the Chicagohenge Saturday morning.
The Chicagohenge is when the sun directly lines up with the city's east-west facing streets during sunrise and again at sunset.
A large crowd of photographers gathered at Stetson and Lake on Saturday night, trying to get the shot. And though the alignment of the sunset and the buildings wasn't perfect, people still had fun.
But, it lasts about a week or so around the Spring and Fall Equinox which is around March 21 and September 21 most years.
Why does this happen?
Throughout the year, the sun sets and rises at different points on the horizon. In the winter, it is a little farther to the south and during summer it is a little farther to the north. But during the equinoxes, with the east-west grid layout of the city, we have the perfect opportunity to see "Chicagohenge."
The Equinox is when the sun's direct rays are right on the equator. "Equinox" means equal day and equal night. So every place on Earth has about 12 hours of daylight and 12 hours of night.