A bit of a one-move-wonder, this one. But that can be good if it's one move that suits you. The move in question is a strong pull off the ground using a good undercling over your head. If you can do that and lean out left, you'll have the big friendly holds of a salmon circuit problem to see you through to the top.
Yes, it starts with a hard move to pull off the ground using that undercling, then moves left to the crack. Bleau.info has a good video.
No Climbing Today!
Rain sucks, but broken holds suck even more. Remember, never climb on wet rock in Fontainebleau.
The sandstone becomes brittle, and pulling on it will ruin classic problems. Drying it doesn't help, because it's still wet and weak inside.
All you can do is wait for better conditions.