In reply to paul birch:
I was there towards the end of March this year. Before going to Tafraoute we'd had 5 or 6 days on the north side climbing in shorts and T shirts. Lovely blue sky, nice and warm... perfect. Same as the year before. Then we moved to Tafraoute. Did a route on Anergui and it snowed that night and settled at a level below where we'd been climbing. Then we had 3 days of rain and high winds before it cleared up and we had a final day back in shorts and T shirts.
Be prepared for anything if you're climbing high... I've bought one of those superlight down jackets to take this year for when we're doing the high multi-pitch routes on the south side ie Tafraoute. It only weighs 350g so seems well worth it.