Hello.

"Wizards Islands"'s Readme says that If player leaves the island until the main quest is completed the mod will break. Is it safe to mark and recall to Vvardenfell and back or with multiple teleport points mods? Will this break the scripts or something?

Sorry for bad english.

Since this has been sitting here for a bit and no one's said anything, I don't think very many people here have experience with that mod. It's not talked about much, that's for sure, and, IIRC, it's rather old, which tends to mean that finding reliable information on its inner workings can be a task unto itself. My advice is to set up a separate save file strictly for testing, where you teleport off and on the island at various points to see if it breaks anything. Only way to be certain.

P.S.: I've seen worse English from people who speak it as a first language.

I think one of the things that happens is that the mod affects the weather and you will see snow and winter weather in inappropriate places on Vvardenfell .

Yes, snow will follow you wherever you go. You might not be able to levitate anywhere either.