YOU SAID:
rain in cats and dogs
INTO JAPANESE
猫と犬に雨が降る
BACK INTO ENGLISH
rain on cats and dogs
INTO JAPANESE
猫や犬に雨が降る
BACK INTO ENGLISH
It rains on cats and dogs
INTO JAPANESE
猫にも犬にも雨が降る
BACK INTO ENGLISH
It rains on cats and dogs
Come on, you can do better than that.