In reply to SFrancis:
Overall its a tricky place to escape the heat, however:
We were there in April when it was low to mid 20s. The higher crags seemed very prone to catching the wind, especially in the afternoons. So even though they're isn't much wind forecast, I suspect that only refers to the town and the exposed crags could be more tolerable. Exposed crags would be places like chambre du roi and vire du inter
Regarding shade, that side of the valley is south facing, so there aren't many exceptions! Again Chambre du Roi had some shade (not in all the routes, but enough for a first visit I think). The sport routes on the boulders as you walk up probably aren't worth traveling far for but they are genuinely fun, and fully in the trees, so they are a possibility of you need a break from the sun. They are on large free standing boulders so face all directions.
Another option, which is only really one route (but it's a good one) is Les Portettes Face, which is right at the top of the hill. High enough up that in April the flora hadn't yet started it's Spring growth whereas the valley floor felt balmy. Its on the trees so is likely shady.
Let me know if you'd like any specific route / sector info.
