It’s raining. The heavens have opened. It’s a torrential downpour. Great sheets of rain are pouring down. It’s raining sideways. All those descriptions of precipitation make a certain amount sense.
But what about when we look outside the window to see a major storm and say, “Wow, it’s raining cats and dogs!” Evocative yes, but as a metaphor, it’s pretty lame. It’s one of those things people say without thinking about it. Not even heavy raindrops look anything like furry mid-size animals. So where did the expression come from anyway? No one is quite sure, though there are several mythological explanations and a few historical citations.
One popular mythological explanation involves Odin, the fierce Norse god of wisdom, battle, healing, frenzy, and tempests, who was often pictured with animals, particularly dogs and wolves. So when the Norse god was throwing down rain, he was throwing dogs. But that doesn’t account for the cats. So maybe “Cats and dogs” comes from the Greek expression cata doxa, which conveniently sounds like cats and dogs and means “contrary to experience or belief.” So when you can’t believe how hard it is raining, it’s raining “cats and dogs.”
A commonly repeated, if slightly unbelievable, folk tale has it that in olden times, domestic animals would make nests in thatched roofs. A heavy downpour would wash the animals out of the thatch, causing them to tumble down to the ground, so it would appear to be literally raining cats and dogs. Upon closer inspection, this theory doesn’t hold up well: cats might conceivably leap up onto a roof to make a home, but dogs aren’t generally that nimble.
Ano a her dubious claim has it that before British towns had decent drainage and sewer systems, heavy storms caused severe flash flooding, drowning dogs and cats, whose bodies would float for days later. People might’ve thought the dogs and cats had fallen from the skies, like a Biblical rain of frogs.
In literature, a similar-seeming phrase turns up as early as 1651. In a collection of poems called Olor Iscanus, the Welsh poet Henry Vaughan writes: “Themselves with a Roofe that can secure/Their Sares from Dogs and Cats rain’d in shower.” The phrase must have had some currency at the time, because in 1653, the English playwright Richard Brome penned a line in City Wit: “It shall raine … Dogs and Polecats.” Today in the American South, which inherited many of its idioms from the U.K., “polecat” is synonymous with skunk.
In the next century, the phrase was indisputably appropriated by Jonathan Swift, a prolific writer and master of deadpan satire who delighted in undermining authority. In a 1710 poem, A Description of a City Shower, his evocative language is calculated for exaggerated gross-out effect: “Sweeping from butchers’ stalls, dung, guts, and blood;/Drown’d puppies, stinking sprats, all drench’d in mud,/Dead cats, and turnip-tops, come tumbling down the flood.” Indeed, this poem harkens back to the idea of drowned animals floating in city streets.
The phrase also appears in its modern form in Swift’s 1738 book A Complete Collection of Polite and Ingenious Conversation, in which he satirizes the conversations of the upper classes: “I know Sir John will go, though he was sure it would rain cats and dogs.”
Other countries have even more bizarre idioms, according to Mental Floss. In South Africa, they say “It’s raining old women with clubs.” In Argentina: “It’s raining dung head-first.” In Slovakia: “Tractors are falling.” In Ireland: “It’s throwing cobblers’ knives.”
While we don’t know where the phrase came from, and say “it’s raining cats and dogs” without thinking of Fido and Fluffy falling from the sky, one thing we can say for certain: Take your umbrella.