Definition
This idiom is used to describe very heavy rainfall.
倾盆大雨
It's really raining cats and dogs today! I've never seen rain like this before.
今天真的下起了倾盆大雨！我从未见过这样的雨势。
We were planning to have a picnic, but it's raining cats and dogs outside.
我们原本计划去野餐，但外面下起了倾盆大雨。
It was raining cats and dogs when I went to work, and I got completely soaked.
我去上班的时候下起了倾盆大雨，全身都湿透了。