Alpine August: clear mornings, stormy afternoons

Chamonix sits under a clear sky this morning, yet the valley is climbing towards 30 degrees. That heat has a cost. By early afternoon the moisture lifts and thunderstorms build over the ridges; today's forecast already shows rain stacking up, with more of it tomorrow. Summit early, be off the exposed sections by one o'clock, and carry a shell even when the morning looks flawless.