I honestly haven’t stopped to consider it. The Wind in this game has a lot of detail too it, so i wouldn’t at all be surprised if the clouds were Dynamic. I’ve also noticed that the Sky can be clear sometimes to depending on weather/season. But that could be just a region of the texture or there are a few different textures. if i had to take a guess i’d say it’s dynamic though. Ubisoft cheaps out on a few things, but graphics doesn’t seem to be one of them