In reply to henwardian:
My local guiding mates all consider September the best month for Dolomite climbing with early October normally good too (sometimes even into November). True, the days are shorter, nights are colder, but you are spared the excitement of electrical storms, not to mention being boiled alive in the midday sun as in July and August. The cliffs are also deserted, which is no small detail.
Obviously as the season progresses you have to move downhill a bit, and you logically end up in Arco, where you can big wall climb right through the winter.
As Mike says above, this year was a freak, with GB style weather all summer. The best weather so far this summer started on Monday 22 September and looks to endure (one rainy day tomorrow) into the foreseeable future.
So the answer is that the next two weeks will probably be good. After that toss a coin (i.e. 50/50). November is a long shot for the Dolomites, but Arco is nearly always good then. My advice is to AVOID July and the first half of August.