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Red rainbow over Bellingham, Washington

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May 4, 2020

Double rainbow over what looks like an apartment complex. — Lawrence Wong caught this photo on May 2, 2020, and wrote: “Just minutes before sunset and after raining, this double rainbow showed up on the eastern side of the sky. I gripped my camera and went outside and took several photos. This is one of them showing orange and red color inside the rainbow.”

Lawrence, you’ve caught a double red rainbow – a cousin to an ordinary multi-colored rainbow – that happens when the sun is low in the sky.

See how tall your rainbows are? The height of a rainbow corresponds (inversely) to the height of the sun in your sky. High sun, low rainbow. Low sun, high rainbow. So rainbow-watchers would know, without your having mentioned it, that the sun was low.

Now think about low suns for a moment. They typically appear reddish. That’s because – around sunset – you’re looking at the sun through a greater thickness of atmosphere than when the sun is high in the sky. At such times, the blue and green components of multi-colored sunrays are weakened by scattering during their long journey through the atmosphere to your eyes.

So red sunsets and red rainbows go hand-in-hand.

Thank you, Lawrence!

Bottom line: Photo of a red rainbow over Bellingham, Washington, on May 5, 2020.

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May 4, 2020

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Deborah Byrd

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Deborah Byrd (asteroid 3505 Byrd) helps edit EarthSky.org and is a frequent host of EarthSky videos. Deborah created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Prior to that, she had worked for the University of Texas McDonald Observatory since 1976, and created and produced their Star Date radio series. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named in her honor in 1990, a Public Service Award from the National Science Board in 2003, and the Education Prize from the American Astronomical Society in 2020. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.