|A webcam on the Point Helbronner courtesy of the Valle d’Aosta tourist board|
The chamonix-meteo weather forecast is usually very good. Generally issued at about 08:30. Sometimes at about 8:30 the page doesn’t load while they update it.
The meteo.fr Chamonix weather forecast covers 4 days and is generally fairly accurate. Their country report is also useful for spotting trends heading across the country. And the Avalanche Bulletin for Haute Savoie (in French).
The snow-forecast.com has a 6-9 day temperature & snow forecast for 3 different altitudes in all European resorts (click on the altitude to see the Chamonix forecast).
The Compagnie du Mont Blanc lift status is useful, generally updated anywhere between 07:30 and 08:30. It also reports wind direction and speed, and snow conditions in each ski domain.
The pressure charts at westwind.ch are very good if you know how to do your own forecasting.
The NASA Global Composite Weather Satellite is great for getting the big picture.
The windguru.cz wind forecast for Chamonix (for snowkiting and paragliding).