It's raining cats and dogs Informal

It is raining extremely heavily.

It’s a playful, exaggerated way of describing a downpour, used casually rather than in any technical or serious weather report.

No single origin is confirmed, and language historians treat this as a genuinely disputed case rather than a settled one. Popular theories include: dead cats and dogs washed through 17th-century British streets during heavy storms and mistaken by later generations for having fallen from the sky; a garbled borrowing from an obscure Greek phrase for something unlikely; a corruption of the rare French word “catadoupe,” meaning waterfall; and Norse mythology, in which cats supposedly influenced storms and dogs accompanied the storm god Odin — though etymologist Michael Quinion notes bluntly that “there is no evidence… for any connection between the saying and the mythology other than the flat assertions of writers.” The most credible documented link is to Jonathan Swift, whose 1710 poem describes dead animals swept along in floodwater and who used the specific phrase itself in his 1738 “Polite Conversation” — leading some scholars to suspect Swift himself may have coined or at least popularized the wording, as part of a broader English tradition of comparing intense rain to absurd falling objects (compare “raining pitchforks”).

Don’t forget your umbrella, it’s raining cats and dogs out there.

We got soaked, it was raining cats and dogs.

The game was cancelled because it was raining cats and dogs.

A: “Should we walk or drive?” B: “Drive, it’s raining cats and dogs.”