rain cats and dogs
To rain cats and dogs is to rain very heavily. The metaphor behind the phrase is that of a dog and a cat fighting, something noisy and violent. The metaphor of a storm resembling a dog and cat fight dates to the mid-17th century, although the phrase, as we know it today, doesn’t appear for another half century. Henry Vaughn’s Olor Iscanus of 1651 goes:
The Pedlars of our age have business yet,
And gladly would against the Fayr-day fit
Themselves with such a Roofe, that can secure
Their Wares from Dogs and Cats rain’d in showre
And a year later Richard Brome writes in his The City Witt:
It shall raine...Dogs and Polecats
The phrase in its modern, familiar form appears in Jonathan Swift’s Polite Conversation, written circa 1708 and published thirty years later:
I know Sir John will go, though he was sure it would rain cats and dogs.
This work of Swift’s is a satire on the use of clichés, so the phrase was probably in use for a considerable period before this.
Despite having a simple and obvious explanation, the phrase has inspired a number of fanciful origin stories that at best have little evidence to support them and at worst are obvious hoaxes.
Perhaps the most famous is the internet myth that states the phrase is from the fact that dogs and cats (and other animals) would live in thatched roofs of medieval homes. Heavy rain would drive the cats and dogs out of their rooftop beds; hence the phrase. This is just patently untrue and displays total ignorance of the qualities of thatched roofs.
Another explanation, this one with a bit more behind it, claims that the phrase is a reference to heavy rains in London drowning stray cats and dogs, leaving the streets looking like the animal carcasses had fallen from the skies. Again we turn to Swift, who uses this imagery in his 1710 A Description of a City Shower:
Drowned puppies, stinking sprats, all drenched in mud,
Dead cats and turnip-tops come tumbling down the flood.
But as the phrase was in use before this, including by Swift himself, it is unlikely that he is being literal here. The imagery is meant to be evocative, not necessarily an accurate description.
Other proffered explanations include the idea that the phrase is from the archaic French catdoupe, meaning waterfall or cataract, or that it uses imagery from Norse mythology, where cats had an influence on the weather, and Odin, the sky god, was attended by wolves.
All of these are unlikely given the early metaphorical uses of cat and dog to signify something noisy and violent. The most likely explanation is the simplest. The noise and violence of a storm is the metaphorical equivalent of a cat and dog fight.
(Source: Oxford English Dictionary, 2nd Edition)
Copyright 1997-2013, by David Wilton