Chamonix and Zermatt stay dry through Monday, with no rain in the forecast. The catch is the morning. Zermatt sat at 6°C at dawn today and should reach 22°C by Sunday afternoon. Start early and you walk into the cold. A light fleece earns its place in the pack. By Monday, Zermatt tops out near 16°C, so the warm window is really Saturday and Sunday.
Fleeces ↗