Sulani Island Festivals - When Do They Happen?

I really wish they'd give notice for these. Yes, we do get a lot of unnecessary notifications. They could cut back on those and give us notifications for island events. I'd be happy even if the notices only happened while you were in one of the island neighborhoods. As it is, my sims have not left the islands yet and I have not seen a single festival.

Hopefully, someone will make a mod for it as I doubt it will get patched in since it would be useful.