Evidence status: UNKNOWN

Heavy rain has produced plenty of colourful expressions, but few are stranger than claiming that household pets are falling from the sky.

People have been trying to explain “raining cats and dogs” for centuries.

So far, nobody has proved where it came from.

The Short Answer

“Raining cats and dogs” has been used for extremely heavy rain since at least the eighteenth century, with closely related expressions appearing during the seventeenth century.

Jonathan Swift used the familiar wording in 1738, but similar images of raining dogs, cats and polecats were already in print before then.

Many explanations have been proposed — from drowned animals in flooded streets to Norse mythology, thatched roofs and old words for waterfalls — but none has been conclusively demonstrated.

The responsible answer is simply:

we do not know exactly why heavy rain became associated with cats and dogs.

What We Know

The expression is genuinely old.

In 1651, Welsh poet Henry Vaughan referred to a roof being secure against “dogs and cats rained in shower.”

Around the same period, playwright Richard Brome used a similar image involving dogs and polecats.

Neither example is identical to the phrase we use today, but they show that the strange combination of violent rain and animals was already circulating in seventeenth-century English.

Then comes Jonathan Swift.

In 1738, Swift published A Complete Collection of Genteel and Ingenious Conversation, a satire on conventional upper-class conversation.

One character remarks that it might “rain cats and dogs.”

That is the familiar modern form.

Whether Swift invented it is another matter. Because earlier animal-and-rain expressions already existed, it is quite possible he was repeating or refining language his readers would recognise.

How It Became a Habit

English has always enjoyed extravagant descriptions of bad weather.

Rain can come down in buckets.

It can rain stair-rods.

Pitchforks have also fallen metaphorically from the sky.

The point is not realism.

It is exaggeration.

“Raining cats and dogs” creates an instant picture of weather so chaotic that ordinary rain is no longer sufficient to describe it.

Once Swift and later writers helped popularise the phrase, the image was memorable enough to survive long after its original logic — whatever that may have been — was forgotten.

The Story Everyone Tells

One particularly widespread explanation involves old houses with thatched roofs.

According to the story, cats and dogs supposedly slept inside or on the thatch.

During torrential rain, the roof became slippery or waterlogged.

The animals then fell through or slid from the roof, giving the impression that it was literally raining cats and dogs.

It is wonderfully visual.

It is also unsupported.

Another popular story points to eighteenth-century city streets.

Heavy rain could wash rubbish, filth and dead animals through poorly drained streets. Swift himself described dead cats and other debris being swept along during a London downpour in his 1710 poem A Description of a City Shower.

Perhaps, the theory suggests, people seeing dead animals after a storm joked that they must have fallen with the rain.

What the Evidence Actually Says

The thatched-roof explanation has no convincing historical support.

There is no documentary trail showing that household pets routinely lived in roofs, fell through them during storms and thereby created the expression.

The flooded-street explanation has slightly more going for it because Swift genuinely did write about dead animals being swept through London streets during heavy rain before later using “rain cats and dogs”.

But that still does not prove one image produced the other.

As Oxford etymologist Anatoly Liberman has pointed out, the true origin remains unresolved, and attempts to derive the phrase from mythology, foreign expressions or forgotten words have also failed to gain decisive support.

So our verdict is:

DOCUMENTED: Animal-and-rain expressions existed in the seventeenth century.

DOCUMENTED: Jonathan Swift used the familiar “rain cats and dogs” wording in 1738.

PLAUSIBLE: Flooded streets carrying dead animals may have influenced the imagery.

FOLKLORE: The popular thatched-roof story is unsupported.

UNKNOWN: We cannot responsibly identify one proven origin.

Why It Stuck

Because it is gloriously excessive.

“It is raining heavily” tells you about the weather.

“It is raining cats and dogs” gives the weather a personality.

The phrase is absurd enough to be memorable but familiar enough that nobody pictures actual Labradors and tabbies falling past the window.

After nearly three centuries, that is quite an achievement.

Related Curiosities

Sources & Further Reading

Library of Congress — “What is the origin of the phrase ‘it’s raining cats and dogs?’”

Reviews the seventeenth-century precursors, Jonathan Swift's 1738 use and the major competing explanations. Read the Library of Congress overview

Oxford University Press — Anatoly Liberman, “Raining Cats and Dogs”

Etymological assessment explaining why the precise origin remains uncertain. Read the Oxford analysis

Phrase Finder — “Raining Cats and Dogs”

Historical examples and discussion of the unsupported popular derivations. Read the Phrase Finder research

Last checked: 19 September 2026