English speakers use the idiom "raining cats and dogs" to describe a heavy downpour of rain [1, 2].
Understanding the roots of such common phrases reveals how language evolves through cultural exchange, mythology, and linguistic drift over centuries.
The expression first appeared in written English around 1651 [2]. While the phrase is now used throughout the English-speaking world, it likely originated in Britain [1, 2]. Despite its prevalence, historians have not reached a consensus on why these specific animals were chosen to describe a storm.
One theory links the phrase to Norse mythology, where cats and dogs were associated with the wind and rain [2]. Another possibility involves a misinterpretation of an old Greek expression describing a "downward flow" [2]. Linguists also point to the Latin word "catadupa," which refers to a waterfall [2].
Some folk stories suggest the phrase comes from animals slipping off thatched roofs during heavy storms [1, 2]. However, this specific explanation has been debunked [1, 2].
Researchers have presented three main origin theories to explain the linguistic curiosity [2]. Because these theories rely on fragmented historical records, no single explanation is universally accepted as the definitive source [1].
“The expression first appeared in written English around 1651.”
The lack of a single, verified origin for 'raining cats and dogs' illustrates the nature of idiomatic evolution. Many phrases survive in common parlance long after their original literal meanings or cultural contexts have vanished, transforming from descriptive observations into abstract metaphors.
