What is when it rains it pours?

"When it rains, it pours" is an idiomatic expression that means when one bad thing happens, often a series of other bad things happen in quick succession. This saying conveys the idea that misfortunes or challenges tend to come all at once rather than being spread out over a period of time.

The origin of the phrase can be traced back to an advertising campaign by the Morton Salt Company in the early 20th century. The company introduced a new product with an innovative anti-caking agent that prevented salt from clumping in humid weather. To highlight this feature, Morton began using the slogan "When it rains it pours" with an image of a girl holding an umbrella and spilling salt from a container. Over time, the expression became widely used in the English language to refer to the tendency for multiple challenges or difficulties to occur simultaneously.

In a broader sense, the phrase can also be applied positively, implying that good things or fortuitous events might also come in a wave, although it is more commonly used in a negative context.