Very cold weather
[1857+; orig referring to a brass figure of a monkey; not, as widely believed, a nautical term relating to cannonballs]
Why, it would have frightened a brass monkey, let alone a man.
"Freeze the ears off a brass monkey," Clark said, joining Don.
And with a roaring fire on a night that's hot enough to melt a brass monkey!
When I got up the second time it was cold enough to freeze the tail off a brass monkey.
"Whew, that'd freeze the ears off a brass monkey," said Nat.
It is cold enough to freeze the nose off a brass monkey, but very exhilarating.
You know well enough, Billy, you haven't got any but that infernal green stuff fit to tan the stomach of a brass monkey.
I might name them as could give me a start and a beating when it comes to talking the nose off a brass monkey.