Yesterday, I did my usual pre-cooking them in the oven for a couple hours in foil. My plan was to finish them on the grill today. That usually just takes 5,10-15 minutes, total to get them nice and dark and done. But it’s supposed to be bitterly cold and too windy to grill. If I finish them in the oven today, how long would I cook them for? And how hot? Thanks, Dopers.
I use this method from Serious Eats. Although the page is about sous vide I don’t think it matters how the ribs were cooked – just follow the part about finishing.
Dry rub finish – 300 degrees for about 40 minutes.
Sauced finish – 300 degrees for 20 minutes – brush on sauce and return to oven for 10 minutes - brush on sauce again and return to oven for another 10 minutes - remove from oven and sauce one more time.
So, fridge to table = 40 minutes @ 300F.
What’s this too cold to grill? 
I would just finish them in an environment as close to however you were going to finish them on the grill. I’d probably just warm it up a bit at 300 and throw it under a broiler for maybe five minutes if you’re glazing and crisping them up. If you don’t do a direct heat step (aka “grilling”), then just follow Turble’s steps.
I don’t understand your question. The ribs have been pre-cooked in the oven and are ready for finishing on the outdoor grill? But you plan to finish them inside? Doesn’t your indoor oven have a ‘broil’ element? Can’t you put them on a broiler pan, ribs seasoned to your liking, and then broil, watching, till they look done? I must be missing something, but this is like the easiest most logical thing imaginable. 
Agreed, with apologies for being dense, I’m unclear about what exactly is your issue.
For some of us ribs are a three day process – day 1 is applying rub or marinade – day 2 is cooking – day 3 is finishing.
The cooked ribs have been refrigerated overnight and must be brought up to temperature before finishing and serving. A few minutes under the broiler won’t do it.
What does “finishing” do? I’m also struggling with how you can’t just toss them under the broiler.
Bringing them up to temp, and then broiling or grilling the outside to crisp up and get a bit of char and caramelization on it. I typically do a straight smoke and don’t bring the ribs up much past 250-275, but every once in awhile, I’ll do a char at the end if I use some kind of glaze or sauce them. (But normally, I don’t glaze or sauce.)
You may or may not be able to throw them under the broiler, but I would guess the outside would burn before the inside is warm enough, depending on the thickeness of the ribs, so bringing them first slow up to temp and finishing is the more sure-fire result.
I’d finish them by eating them. 