• Hat (or cap) for sun protection and/or scarf.
• Glacier glasses (category 4 index) + ski mask.
• A balaclava (like a balaclava that covers the whole head) (very useful in very cold weather)
• 1 pair of very warm mittens.
• 1 pair of fleece or wool gloves.
• 1 pair of inner gloves.
• 2 or 3 breathable, long-sleeved technical underwear.
• Breathable technical base layer (carline, lightweight fleece...)
• Thick fleece jacket.
• Down jacket or vest (not mandatory but appreciated if it is very cold on the day of the summit).
• 1 windproof, waterproof and breathable Gore-Tex type jacket.
• 1 pair of comfortable mountain pants for approach trails.
• 1 pair of Gore-Tex type windproof trousers when you are on a glacier.
• 1 pair of breathable technical tights.
• Socks: 3 thin pairs and 2 thicker pairs.
• 1 night outfit for the evening of Day 3 at the Tour chalet + toiletries
• A few hand and/or foot warmers can be useful for those who get cold easily on summit day
This list is generic and is intended to cover all the weather conditions you might encounter in the high mountains. It should be adapted to the conditions forecast for the day of your stay.
But keep in mind that temperatures drop considerably with altitude and wind chill. Therefore, always pack warm clothing, even when temperatures are high in the valley.