As English is not my first language, when first time I heard “Its raining cats and dogs” – I got stuck in place. It took time for me to understand that I am dealing with an idiom – the falling down from heaven various cats and dogs overfilled my imagination!!!
Recently I searched for the same idiom but in other languages, and here the funniest versions which I have found:
The idiom “Its raining cats and dogs” in other languages and the meaning

Slovak
Tractors are falling
Padajú traktory
Greek
It’s raining chair legs
Rixnei kareklopodara
Brazilian Portuguese
It’s raining frogs’ beards
Está chovendo barba de sapo
Norwegian
It’s raining female trolls
Det regner trollkjerringer
What is an idiom for rainy days in your language?:)
References
How different languages say “It’s raining cats and dogs”, June 27, 2020. The language nerds, available online on: https://ahtaitay.blogspot.com/2020/06/how-different-languages-say-its-raining.html