What's a weird saying?
When examined, or just because it's weird on its own.
Example: Beat a dead horse
"It's raining cats and dogs."
Somehow, heavy rain is represented by a downpour of household animals.
It's previously rained frogs or fish from clouds, at certain times throughout history.
So, cats and dogs is an even more intense version of that maybe.
The household animals are not pouring down. This saying describes rainfall that is so powerful that it washes away the dead cats and dogs lying in the gutter in medieval cities.
Interesting. I always thought it was because the rain was so heavy it drove all the strays to seek shelter, so people noticed a lot more cats and dogs in front of their homes. I think a grade school teacher told me that when I was a kid. I like the dead animal version better.
This one is because when houses had straw roofs, cats and dogs would sit up there, and come down in the rain.