it'll be a cold day in hell

it'll be a cold day in hell

It is unlikely or impossible that it will ever occur. Used hyperbolically and often issued in defiance of some request or demand. It'll be a cold day in hell when I sign over the lease of my land to you. It will be a cold day in hell before the two parties agree to anything.
See also: cold, hell
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

It'll be a cold day in hell (when something happens).

Rur. Something will never happen or is highly unlikely. It'll be a cold day in Hell when the city council agrees on where to build that bridge. It'll be a cold day in Hell when I forgive you.
See also: cold, hell
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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References in periodicals archive ?
We're always being told to use public transport more but I'm sorry, it'll be a cold day in Hell before I shell out that amount for a bus journey into Stirling.