Is that just sometimes because otherwise how does it rain and water get to the trees? And can thunderstorms and lightening form while your in the cloud layer?
yes, that's just sometimes. I believe it has to do with the weather pushing hot air up so the clouds come down or something.
I'm not sure how would it work during a storm, when I climbed down it was just a cloudy day and going through them felt humid as if walking through fog :)