I know some softies don't agree, but I'd go to taipan anytime in winter regardless of how cold it is. I've spent a few days up there when temps didn't even hit 10C and there was no sun, and would happily do it again. on these days it is simply necessary to (a) dress properly so you don't freeze during belay sessions, and (b) do a cardio-type warm up before you climb - if the blood is pumping when you tie in, you keep toasty warm fingers up the whole route (e.g. I often jog up to the top end of Spurt Wall and back down - only takes 2-3 mins and it sure warms you up!).
otoh if its raining its a bit more miserable, and you end up cowering on Spurt.