My experience:
2008 - La Grave Extremely Canadian (booked 6 days). Result: La Grave 4, Serre Chevalier 1, Via Ferrata near Briancon 1.
As there had been no new snow in a month, the overcast day at Serre Chevalier was about 2 hours frozen granular piste skiing plus a gourmet lunch. So when the last day was overcast, they opted for a non-skiing activity.
2008 - La Grave Extremely Canadian (booked 6 days). Result: La Grave 4, Serre Chevalier 1, Via Ferrata near Briancon 1.
As there had been no new snow in a month, the overcast day at Serre Chevalier was about 2 hours frozen granular piste skiing plus a gourmet lunch. So when the last day was overcast, they opted for a non-skiing activity.