Cross the high passes before noon

High summer settles the Alps for days, then breaks the pattern in two hours. The rule on Swiss and French routes: cross any pass above 2,000 metres before noon, and be back at hut level by early afternoon. Thunderstorms build fast up there. The standard Tour du Mont Blanc is snow-free now, but higher variants still hold patches near the Col du Bonhomme. Start early. Check the sky, and turn back if it darkens.