Jonathan Swift’s poem “City Shower” (1710) described floods that occurred after heavy rains. The floods left dead animals in the streets, and may have led locals to describe the weather as “raining cats and dogs.”
Again, we don’t know for certain. Etymologists—people who study the origins of words—have suggested a variety of mythological and literal explanations for why people say “it’s raining cats and dogs” to describe a heavy downpour. Here are some of the popular theories:
- Odin, the Norse god of storms, was often pictured with dogs and wolves, which were symbols of wind. Witches, who supposedly rode their brooms during storms, were often pictured with black cats, which became signs of heavy rain for sailors. 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.