As Kmourn alludes to...this thread should be qualified as to what borderline weather is.
Cold and windy, or just windy I can live with. Add rain into that mix and it becomes downright miserable and I wouldn't want any part of that.
That being said, it is fun to play in high winds if nothing else to watch a well judged shot snuggle up close. Or an ill struck shot go off-line in epic proportions where you're hitting your next shot from 2 fairways over. 
A family member says there are three factors that control whether it's nice enough to play.
Light wind/no wind
No rain
Temp above 50* F.
Any two of the three, and it's golf weather.
Yesterday the wind was pretty light, and the rain/mist was light enough to tolerate most of the time. Every time it turned into real rain, my buddy and I would start to think about heading in--then it would let up.
I have played tournament golf a couple of times with temps in the low 40s, stiff wind and cold rain... it's only fun if you're contending.
Of course, there's one other thing I like about marginal conditions.
It gives me the chance to do "equipment testing." My wife and I will sometimes go play in rotten weather so that the next time we are faced with bad weather during a tournament, we'll have an edge.
Like she says, "Next time we're playing in a bad weather, we can say, 'This is nothing compared to that day we....'"
Ken