What is often forgotten about
Mont Ventoux is the part from Les Bruns to Chalet Reynard. Those are ten really hard kilometres, entirely in a
forest and virtually no switchbacks. This means no wind and hot (especially since Mont Ventoux isn't so high, in an Alpine perspective).
After Chalet Reynard the road climbs steadily following the
contours of the
mountain side so I guess the wind's effect can be rather local. According to wikipedia the Col de Tempêtes (about 1k from the finish) is the windiest part, but with Cobblestones' forecast of 15mph winds, the wind will not be a big factor (as an aside, I don't recall much wind from when I climbed it early July a few years ago). The temperatures doesn't seem extreme either.