Raining very heavily
Most learners of English will be familiar with the idiom It’s raining cats and dogs. Indeed, many people remember it because it’s such an odd expression and one which can conjure up quite entertaining images.
However this idiom is rather old-fashioned. In a polite, formal situation the British might simply say “It’s pouring”, with the optional addition of the slightly superfluous words” with rain”: “It’s pouring with rain” or “It’s pouring down”.
Less formal alternatives is “It’s bucketing down”. If the rain is particularly heavy, the verb “lash down” can be used, as in “It’s been lashing down for an hour now”.
There’s no definitive origin, probable source of ‘raining cats and dogs’ is the prosaic fact that, in the filthy streets of 17th and 18th century England, heavy rain would occasionally carry along dead animals and other debris. The animals didn’t fall from the sky, but the sight of dead cats and dogs floating by in storms could well have caused the coining of this colourful phrase. Jonathan Swift described such an event in his satirical poem ‘A Description of a City Shower’, first published in the 1710 collection of the Tatler magazine.
Il pleut des chats et des chiens
Correct French idiom
Il pleut des cordes