But what are conditions like up there? How do you know if it's snow free or safe to tackle some of the climbing routes? What condition are the routes in? Of course you check the weather forecasts and reports, or take a look at some of the webcams dotted around the valley, but these don't cover all the trails and routes, and they certainly can't give you a first hand account of what conditions are like.
This is where the Chamonix High Mountain Office (OHM) comes in. The OHM publish helpful information on how to organise trips into the mountains, reducing risk and how to get assistance or rescue on their website. They also have a facebook page La Chamoniarde where they post detailed updates on mountain conditions, in English and French. If you're looking for regularly updated information, then make this your go-to place for updates on mountain conditions.