YOU SAID:

It's raining cats, not dogs.

INTO JAPANESE

猫と犬ではない雨です。

BACK INTO ENGLISH

It is not cats and dogs but rain.

INTO JAPANESE

猫と犬が雨です。

BACK INTO ENGLISH

It's raining cats and dogs.

INTO JAPANESE

バケツをひっくり返したような雨だ。

BACK INTO ENGLISH

It's raining cats and dogs.