Lets just say this discussion boils down to how much weight you are willing to carry. This IS an ultra light backpacking forum and I signed up to see what other people were doing to shed weight because I would like to be carrying 30-35 lbs instead of 45lbs on an eight day trip. On one recent trip I ran into a guy carrying a starting total of 18lbs for a 5 day! Course for food he had butter and peanut butter...exclusively...hummm. But the concept interested me. An old rule of thumb (according to my dad) was to carry 20 to 25% of your body weight but this guy was at 10%! It is just a fact that the less you carry the easier time you will have and the less wear and tear on the body.

That said, weather can change fast in mountains. Because of that I tend to be conservative about weather related gear. Do your research and test out your set up. You are the one who needs be happy with it.

One other note. I have worked in Montana in the southwest quarter of the state mapping geology in my youth. It was very nice for most of the 4 months I was there. It did snow on us once in June and once in July. One of those days was a beautiful cold day in the Flint Creek range. A very pleasant day. The other I froze my ass off inside a Dodge Ram Charger with the heater going full blast trying to work. I had my best down jacket on. You know the coldest recorded temp in the lower 48 is in Montana. The point is that you never know so be prepared. Oh yea, I forgot the hail...crazy hail the size of golf balls. The KOA I was staying at looked like a troop of angry boy scouts with ballpeen hammers had attacked. Helena got hit the same day by stuff the size of grapefruit. You could see the dents in the copper dome of the capital building. Kept the glass guys busy for months.