Description:

If you sleep while it's raining, the rain won't stop after you wake up, and it will rain infinitely. Also, undead mobs take damage from rain.

Fix: Quitting and joining back your world fixes it.

Attachment: The file size is too large, so I uploaded it on YouTube:

https://youtu.be/w8C9YnWQkM4

You can see on the video what I mean.

One thing to note is that it was raining nonstop for half an hour. In the video, you can only see the last 2 minutes.