The weather. "Going for a walk in the sun vs/ when it's raining," the text on the video reads. Jens hates the rain, or at least he hates it when the stairs are covered in water.

Additionally, the phrase may stem from the Greek expression “cata doxa,” meaning contrary to belief, implying that if it’s raining cats and dogs, it’s raining unbelievably hard.

First of all, the expression "it's raining cats and dogs" is a well-known English idiom used to describe a heavy rainstorm. Snopes previously wrote about the idiom's origins in an article ...

Jens hates the rain, or at least he hates it when the stairs are covered in water. "Under the weather," the video's caption reads, and people filled the comment section with a lot of love for Jans.