Question

Is the following sentence considered as pathetic fallacy: "The sun disappeared and all was cold and grey."?

Answer 1

Depends on how you connect it to the plot later on.

Explanation:

It can be if in the following events something somber/creepy/scary happens. It will have predicted the upcoming events and matched them.

But it isn't pathetic fallacy if later on something good or anything that doesn't match the mood created by the weather happens.