# that'll be the frosty Friday

idiom

Source: https://englishreference.com/idiom/thatll-be-the-frosty-friday
Updated: 2026-08-10

## Meaning

Synonym of that'll be the day (“said in reply to something that one believes will never happen”).

## Examples

- You think he will pay you back? That'll be the frosty Friday.
- He plans to wake up at five for a run? That'll be the frosty Friday.
- You expect a free meal from that cheap restaurant? That'll be the frosty Friday.
- My brother promised to clean the entire garage by noon, but that'll be the frosty Friday.
- She says she will stop checking her work emails during our vacation, but knowing her, that'll be the frosty Friday.
- The landlord promised to fix the leaky roof by tomorrow morning, though we all know that'll be the frosty Friday.
- When the politician claimed he would lower taxes without cutting any public services, the skeptical voters knew that'll be the frosty Friday.

## Origin

The expression is probably a humorous elaboration of the phrase *that’ll be the day*, with the alliteration of *frosty* and *Friday* chosen for phonetic effect. It is also thought to evoke the image of a cold day in Hell, referencing the proverbial time when Hell finally freezes over. (disputed)

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.