I've been up there on that cable care to Mount Blanc. Temperature went from 85 degrees to 20 F
I had originally planned to propose to my wife up there, but earlier when we were Annecy we were walking along the lake in the evening, had just had a nice dinner, there was some sort of accordion music of in the distance and the time was just right.
In turn, proposal didn't take away from the top of Mt Blanc. It was pretty crowded up there and certainly much less romantic. Still worth the trip up though.