In reply to Andy Syme:
There was another thread asking the same. It takes a couple of weeks of hard frost for the main pitch to come in though the upper pitches do come in to condition more readily. Even a couple of years ago after a fortnight of temps that didn't get above freezing there was still water running though it was climbable (and lots of people did climb it) Have you checked the winter conditions page to see if anyone's logged an ascent recently.
ALC