Marmot Plasma 30

I have one, and have used it in the southern Sierras (Golden Trout, Sequoia, etc). Very adequate for the summer.

Late September I start thinking about carrying a warmer bag, not so much because it's always needed, but that in late September there's more of a chance of weather, especially at higher altitudes.

YMMV.

It is one of the lightest fully featured sleeping bags on the market. That said you could shave 5-6 ounces with a quilt.

You can also check out the stoic somnus 30. A little heavier with the 850 fill, but still has some nice features. Pertex Quantum, zippered foot box pouch, and the hood opening is face shaped so its easy to roll with.Plus its a great price.

My regular length is 26 oz. For reference it has the same fill weight as the marmot hydrogen 30 which, from what Ive read, is pretty accurately rated.

I'd say the Pinnacle is perfect for the Clark range in late September.

But yes, for summer in the Sierra you'd want something lighter. Sorry, no experience with the Plasma.

I have a Plasma 30 and had have good luck so far in the Sierras with it …. for most places during summer in SouthWest, it has been perfect, sometimes a little hot. That being said, I previously had a Helium 15, which I got rid of to cut weight and although I've done well with the Plasma, I'm still concerned about shoulder season trips or storms in general, especially in the Sierras … I'm sure I would be fairly miserable and 20 to 25 in the Plasma, but haven't been there yet …. The Plasma is probably works out being perfect for 90% of summer trips I do … but still need to see how it does below 30 …. If I knew I was going into bad weather I would consider a liner or some other sort of insurance ….