Serious ?? Summer is just ramping up here. Surely there are a few months left in the season. Drones are still flying and have not been kicked out of the hives yet
Not because I don't think a nuc or a new split would do well now.
When you get hives coming into early spring looking like you could split them already, those are the ones I would split. I would not split that hive because you said it isn't quite ready to split yet, and it's December. I would not weaken it this year by splitting it.
But this is based on my limited experience, in my area.