What Causes The Circular Halo? {Explanation Text}

Also known as a 22 degree halo  or a sun halo, the ring is caused by sunlight passing through ice crystals in cirrus clouds within the Earth's atmosphere, the University of Illinois' Weather World Project 2010 explains. (See WW2010's website  for diagrams that illustrate how it works.)

The crystals bend direct sunlight, projecting it elsewhere into the sky, and at a certain angle -- you guessed it, 22 degrees -- a halo can be seen around the sun.

Ever seen a #SunDog  - a ring of light sometimes visible around the #sun ? Here's a cool 1 from @denalinps  twitter.com/Interior/statu… — US Dept of Interior (@Interior) March 6, 2013

While the beautiful sight may complement the springtime weather, the sun halo is not limited to a certain season and can happen anytime, anywhere, depending on the viewer's vantage point and the sun's position. However, the occasional sighting -- similar to a rainbow -- is more common in the fall, winter and spring  "when the northern jet stream descends southward, drawing down Arctic air masses," NASA notes.

source: www.huffingtonpost.com