You may have heard the expression “It’s raining cats and dogs” and wondered what it means.
When someone uses this English idiom, it means that it is raining very heavily. That there is a downpour (heavy rain).
Oh course it has nothing to do with cats, dogs or any other animal falling from the sky. It’s just an idiomatic expression that started a long time ago (nobody is exactly sure how it started) and it continues to be used until today.
You might want to check out more English idioms about the weather.
Or maybe just learn other vocabulary about the weather.