Weather Education: Crepuscular Rays

Weather Education: Crepuscular Rays

Sometimes you’ll find yourself bathed in a spotlight of sunlight, streaming out of the clouds at slanted angles. Those alternating bands of light and shadow are crepuscular rays; their name comes from the Latin word for twilight, when they are most easy to see.

The effect comes depends on having a lot of particles in the atmosphere, such as dust, moisture, and pollutants. When the sun’s rays hit those things, their light scatters into a beam that we can see. The clouds encasing the light need to be darker and shadowy to give that strip of light edges.

Courtesy of the NWS

All together, this makes for a concentrated band of light. Depending on where the sun is in the sky, they can have tinges of colors different from their typical yellow.

And in reality, those rays aren’t actually going off in crooked directions. They’re shining in straight lines, but because we are so far away from the sun, our perspective makes it look like all the rays are getting narrower towards it.

Courtesy of the NWS

Want to learn more? Check out all of Jeff’s Weather Education posts here!

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