cold as a mackerel

Meanings

adjectivecold as a mackerel (not comparable)

not comparablesimileVery cold (in temperature, emotionally, etc.).
In some areas our audiences enjoyed the music; in others they were cold as a mackerel.
1988, Garvin Bushell, Mark Tucker, chapter 16, in Jazz from the Beginning, Ann Arbor: University of Michigan Press, page 131
2 more examples
1920, Fire Service (Official organ of the Fire Marshals’ Association of North America, and Eastern Association of Superintendents of Fire and Police Telegraph), 6 March, 1920, p. 7, “I tell you, Governor, that in those days they weren’t ashamed to have a little good liquor around to warm the insides of a man weary and as cold as a mackerel from an all night job.”
At that raw spring hour, mid-February or early March, the sky would be as beautifully cold as a mackerel, bluish-white at its base, everywhere else a dark bruise-blue except where gas lamps in the streets let in a pale green-whitish-yellow,
1964, Seán Ó Faoláin, chapter 4, in Vive Moi!, Boston: Little, Brown, page 61
Synonyms: stone cold
not comparableCompletely unconscious.
She had just slid forward in a pile in front of the chair, on top of her nice hat. She was as cold as a mackerel.
1942, Raymond Chandler, chapter 27, in The High Window, New York: Knopf, published 1964
1 more example
He said: Queenie, I think I’m going to pass out and before I do, I’m going to give you a piece of advice […] and he said quite solemnly: Queenie, always stick to Bach and the early Italians—and passed out cold as a mackerel.
1961, Walker Percy, The Moviegoer, New York: Knopf, Part 4, p. 136
Synonyms: out cold