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n. Chiefly Northeastern US
A sky covered with many small cirrocumulus or altocumulus clouds, resembling the markings found on a mackerel. Also called regionally buttermilk sky.
(Physical Geography) a sky patterned with cirrocumulus or small altocumulus clouds
[from the similarity to the pattern on a mackerel's back]
a sky marked by cirrocumulus or altocumulus clouds scattered like the markings on a mackerel's back.
mackerel sky- One with rows of white fluffy clouds resembling the pattern on a mackerel's back.
See also related terms for rows.