What is the origin of the phrase 'raining cats and dogs'?

The first recorded use of a phrase similar to “raining cats and dogs” was in the 1651 collection of poems Olor Iscanus. British poet Henry Vaughan referred to a roof that was secure against “dogs and cats rained in shower. read more

Therefore, “raining cats and dogs” may refer to a storm with wind (dogs) and heavy rain (cats). “Cats and dogs” may come from the Greek expression cata doxa, which means “contrary to experience or belief.” If it is raining cats and dogs, it is raining unusually or unbelievably hard. “Cats and dogs” may be a perversion of the now obsolete word catadupe. In old English, catadupe meant a cataract or waterfall. read more

Another suggestion is that 'raining cats and dogs' comes from a version of the French word 'catadoupe', meaning waterfall. Again, no evidence. If the phrase were just 'raining cats', or even if there also existed a French word 'dogadoupe', we might be going somewhere with this one. read more