It's raining cats and dogs
US /ɪts ˌreɪnɪŋ ˌkæts ənd ˈdɔɡz/
UK /ɪts ˌreɪnɪŋ ˌkæts ənd ˈdɔɡz/

1.
llover a cántaros, llover a mares
raining very heavily
:
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I can't go out now, it's raining cats and dogs!
No puedo salir ahora, está lloviendo a cántaros!
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We had to cancel the picnic because it was raining cats and dogs.
Tuvimos que cancelar el picnic porque estaba lloviendo a cántaros.