Would a 15 degree bag not be warm enough for Aconcagua? I was planning on wearing my belay jacket if it gets really cold. Also, I am going to bring it to Kili which I dont think I am going to have a problem there.

thanks,
Blake

I think you would be ok with a 15degree bag as long as it doesnt get really cold, and if your not planning on sleeping above Nido. Although i would suggest getting a liner to go outside your bag. You can pick them up at REI for like 30 dollars and they are rated to 50 degrees but when combined with your other bag should make it about 5-10 degrees warmer. Thats what I did and it worked very well. It was also nice to have the lighter bag at confluencia and base camp.

I used a 15 degree bag on the Polish Glacier Route five years ago. It got a little chilly at the high camp, but I brought a fleece liner that adds another 10-15 degrees and slept quite comfortably. Just make sure your 15 degree bag is for real a 15 degree age, i.e. not a 600 fill down bag from 10 years ago that has been used 5,000 times.

In mid-December last season climbers were freezing at the Plaza Argentina base camp while wearing their down jackets and numerous tents were destroyed at the 19,200' high camp over several weeks of bad weather.

I don't know your situation but you may be OK with a 15F bag depending on conditions and how warm you sleep at night. For me, however, I would be concerned about jeopardizing all the time, effort and money I put into the climb if I was deciding between a 15F and the 0F bag I would normally take on this climb.

I couldn't agree more Brad. You're asking for trouble not being prepared for typical night time temps. It's not unusual for it to hit single digits, or below zero degrees (F) at night at high camp. Sure you can survive that in a 20 degree bag, but will you be rested enough to climb the next day? Pony up a few extra bucks for a liner and eliminate the risk altogether.

Add my name to the list with Brad and Alpinist. Take a warm bag. I have a -20º bag that I have been cold in at the high camp. It's hard enough sleeping at 19,000 feet with the altitude. Being cold or having to wear everything in your bag is uncomfortable to say the least. IMHO. Cheers William