clothes to bring for hiking in Chamonix

Layers, depends on what altitude you're going to but a polypro/wicking underlayer, wool sweater layer, and an outer layer that is windproof and water resistant such as goretex or similar material. Cotton is useless once it gets wet (from precip or perspiration).Important: Temps in the mountains are proportional (inversely) to altitude and also affected by wind. If it's 70F where you're sleeping at 2000 feet it will be in the low 40s at 10000 feet and will feel even colder if there is wind at 10000 ft that was not present lower down. Temp decreases ~3.5 degrees F for every 1000 foot increase in altitude.

We were suprised at how cold Chamonix was last June for us. Even in town it was fondue weather in the evening. The Mt. Blanc gondola crossing was closed due to heavy ice and snow. I would go with layers and know that there are plenty of places to purchase gear when you are there.

When we were in Chamonix June '05 it was very warm, in the mid 80's. Every year is different. In June '06 we were in Murren and it was very warm there also. This July we'll be in Chamonix and Murren again. We like to pack very light and what works for us is a tee shirt, fleece jacket and windbreaker...that, plus hiking keeps us warm enough.

At the bottom is warm, but up in the mountains you will find snow. We took the cabin up and on the other side of the mountain in Italy and it was very windy and a lot of snow in August.
I am a pro layering and microfleece tops. I can't stand fleece pants though. For sure you will need a coat, hat and gloves.
There are many good web sites and forums about hiking in Alps you can check out.

I have a coat that's fleece inside and windbraker fabric outside.It's very soft and can be packed small.
I am cold most of the time, but this coat keeps me very warm at all times. It's made by Sierra.