These are cirrocumulus clouds. When the clouds in the sky look like this picture, it is called a "mackerel sky" because the clouds look like the scales on a mackerel fish.
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Courtesy of UCAR Digital Image Library

Cirrocumulus

Cirrocumulus clouds (weather symbol - Cc) are composed primarily of ice crystals and belong to the High Cloud group (5000-13000m). They are small rounded puffs that usually appear in long rows. Cirrocumulus are usually white, but sometimes appear gray. Cirrocumulus clouds are the same size or smaller than the width of your littlest finger when you hold up your hand at arm's length.

If these clouds cover a lot of the sky, it is called a "mackerel sky" because the sky looks like the scales of a fish. Cirrocumulus are usually seen in the winter time and indicate fair, but cold weather.


Last modified September 25, 2007 by Becca Hatheway.

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