Apparently not, if commenter Thirith speaks true:

For those interested: I had a quick PM exchange with Larian, and there won’t be a day/night cycle in D:OS 2 either. Not a deciding factor, but something that would’ve got them closer to their self-avowed goal of making a worthy spiritual successor of Ultima VII.

I believe my only response to this is:

Or possibly:

For what it’s worth, I’ve not asked Thirith for any sort of proof that this conversation took place, and for what it’s worth Larian still have the Day & Night Cycle suggestion on their Game Ideas survey forum.

That said, one of the commenters there did explain in some detail just what level of work would be involved to fully implement NPC schedules (which Larian have said, in the past, that they’d want to include for sure if they did implement day/night cycles; having the latter without the former is, in their thinking, immersion-breaking), so I could see why Larian might once again choose to sidestep these features. I really hope they don’t, and I’d be disappointed if they did, but…I can see why they might.