Prepare your outing in the Chablais
Check the weather before you go. :Local weather with Chamonix Météo by phone at 08 99 71 02 74 (voice weather report) or on the website + the excellent app Swiss Weather
Find out about ongoing roadwork. These are usually done in spring or autumn and some passes may be closed or difficult to pass, especially on the way down. For your information: 04 50 66 10 74 or on the website
Some high passes close in winter. Learn about the opening status of the passes by clicking here