YOU SAID:

haha its raining cats and dogs

INTO JAPANESE

ハハ、雨が降っている猫と犬

BACK INTO ENGLISH

haha it's raining cats and dogs

INTO JAPANESE

猫と犬が雨が降っています。

BACK INTO ENGLISH

It's raining cats and dogs.

INTO JAPANESE

大雨です。

BACK INTO ENGLISH

It's raining cats and dogs.