In reply to im off:
It's difficult to say, but looking at the meteo numbers, it seems to me that there might still be snow on the North face, especially the upper part, by Saturday. All I would say is that you shouldn't underestimate how much harder it would be if there is, and take into account that the exit chimneys are very likely to be icy. All this then means having to take a lot more gear than we took when we did it in early August last year (which, as it happens, was rather less than we should have!).
Have you done the North Ridge? If you don't mind doing that (I haven't, but it looks brilliant) then you could go up to the hut and decide when you get there. You don't really get a good look at the face until you get right up to the Notch, but you can easily change your mind and do the Ridge if you don't like the look of it.
