# Weird rainbow effect **URL:** \ **Category:** Factual Questions\ **Created:** [February 8, 2001, 11:42pm UTC](https://boards.straightdope.com/t/weird-rainbow-effect/53709 "2001-02-08T23:42:26Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Mr.Blue\_Sky](https://avatars.discourse-cdn.com/v4/letter/m/d26b3c/32.png) [@Mr.Blue\_Sky](https://boards.straightdope.com/u/Mr.Blue_Sky)\ **Post date:** [February 8, 2001, 11:42pm UTC](https://boards.straightdope.com/t/weird-rainbow-effect/53709/1 "2001-02-08T23:42:26Z")
While driving home today, I looked toward the west where the sun was on its way down (5:00pm EST) and to the left and right about a palm’s width from the sun, there was a small thumb-sized rainbow segment. The two segments stayed there until some clouds completely obscured the sun. Any ideas as to what would cause this sorta thing? ---
**Author:** ![rjk](https://avatars.discourse-cdn.com/v4/letter/r/ed655f/32.png) [@rjk](https://boards.straightdope.com/u/rjk)\ **Post date:** [February 9, 2001, 12:16am UTC](https://boards.straightdope.com/t/weird-rainbow-effect/53709/2 "2001-02-09T00:16:05Z")
They’re called ‘sundogs’. and are pretty common if the climate is right - cold and clear. The cause is ice crystals high in the atmosphere that reflect the light much the same way that water droplets refract it in a rainbow. Because it’s reflection, they appear near the sun (at a fixed angle), instead of opposite. Google returned this site, and many more: [http://antwrp.gsfc.nasa.gov/apod/ap990823.html](http://antwrp.gsfc.nasa.gov/apod/ap990823.html) ---
**Author:** ![Mr.Blue\_Sky](https://avatars.discourse-cdn.com/v4/letter/m/d26b3c/32.png) [@Mr.Blue\_Sky](https://boards.straightdope.com/u/Mr.Blue_Sky)\ **Post date:** [February 9, 2001, 12:31am UTC](https://boards.straightdope.com/t/weird-rainbow-effect/53709/3 "2001-02-09T00:31:15Z")
Add this to my “learn something new every day” file. That’s exactly what I saw. Thanks rjk!