High pressure is holding over the Western Alps into Tuesday. Zermatt, at 1,608 metres, started this morning at 9 °C and should reach around 23 °C by afternoon. Chamonix stays dry through Monday too, with lows near 13 °C in the valley. That is a big swing. Start in a fleece, finish in a T-shirt. Pack the fleece anyway: temperatures drop fast once the sun leaves the valley.
Fleeces ↗Dry autumn days in the Western Alps: dress for the swing
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