I will be hiking in the Teton range of Wyoming end of August/ beginning of September. Temperatures could get into the low 20's. Is this bag warm enough? I can always wear extra layers, but would hate to get too cold. I generally sleep hot and do not need lots of insulation. I have considered the 15 degree bag from Montbell, but it is heavier and more expensive. Any advice?

uhhh...this bag is rated at 30*F, you think it might get down to 20*F?????? What is your question??????

If you go with the 30 and you are cold - try putting a water bottle filled with hot water between your legs when you go to sleep - it helps to warm you extra clothes and the bag.

i am the same way. i can usually get away with a 30 degree bag in 20 degree weather because i sleep on two pads. just because you wear more clothes does not mean you are going to be warmer. your body has to warm those clothes up too. i would personally be ok with it as long as i had a closed cell foam pad and an inflatable underneath. the further you can distance yourself from the ground the better. again, i personally would be ok with it for me (as i have slept in my mountain hardwear ultralamina 32 with lows in the mid teens), but i cannot in good conscience recommend that someone else do the same. i would hate to feel responsible for your hypothermia, or at the very least, you not sleeping because you are cold. so basically, its up to you. i dont know that i would push it in the Mountains. i think you would be happier with a colder rated bag with the ability to open it up than have a higher rated bag and suffer.