This might sound glib, but I don't mean it that way at all. I mean to give a serious answer. I don't think this is the sort of question that is best answered with a formula.
Q. When do you club up in cold weather?
A. When it's cold enough that your standard club won't get there.
Seriously, there's no need to make a science of it: just get a feel for how far you are hitting it, and adjust accordingly.
In my experience playing with a lot of different golfers over the past year (I have no regular foursome), I think most amateur golfers are far too hesitant to take an extra club when conditions change. I played a week ago in some very stiff wind for around here (20 to 25mph) and I was playing with a couple of decent young players who could both broke 90. But dead into the wind they would often only take 1/2 or 1 club more. They would then invariably swing harder. Most of the time this would lead to a bad miss, but when they hit one solid they would spin it up in the air and come up way short. I was playing with one guy who is usually about a half a club shorter than I, but on into-the-wind holes I would be hitting 2 to 3 clubs more than him because I was hitting 2 to 3 clubs more than I usually do.