"a mackerel sky"
King mackerel
Public DomainKing mackerel - Credit: NOAA's Fisheries Collection

A mackerel sky, so-named because of its similarity to the markings on a king mackerel's back, is a sky dappled with clouds of the cirrocumulus, or altocumulus type. It is occasionally known as a buttermilk sky.


Mackerel sky
Creative Commons AttributionMackerel sky - Credit: Hilary Chambers