Can a semi-rectangular bag keep me warm enough in the Colorado Rockies?

I find mummy bags to be really confining. I understand the point, of course, but I'm a side sleeper, and I like to lay "can-opener-style." (You know, with one leg pulled up and the other straight.) Can this question get any more awkward? Anyway, do you have any suggestions for sleeping bags that are a little less crped but would still keep me warm from April to mid-October in the Colorado Rockies? Sarah Boulder, Colorado


We like people who go into confessional mode here. Anything else you care to share? But what you say makes perfect sense. I’m a knees-up side-sleeper, and that doesn’t always work well in mummies, either.

Western Mountaineering Sycamore MF Sleeping Bag

Sycamore MF Sleeping Bag

So you’re looking for about a 20-degree bag? That should get you through the shoulder seasons in the Rockies. One possibility is the Big Agnes Roxy Ann +15 ($200; It’s a women’s-specific down bag rated to 15 degrees. It has quite a roomy cut, so you should be able to do your can-opener thing in comfort. The one down side is that it’s fairly heavy, at nearly three pounds.

The best design for sleep comfort is semi-rectangular: wider than a mummy, but not a full rectangle. Alas, that’s a part of the market that doesn’t get much attention, and most bags in this category tend to be heavy and made with inexpensive synthetic fill. Nothing wrong with them, they’re just best for car-camping.

But there is one exception. In my humble opinion, the very best light/warm/roomy sleeping bag is the Western Mountaineering Sycamore MF ( It’s rated to 25 degrees, has loads of 850-fill down, and is made with a roomy semi-rectangular design. Weight is two pounds, and it packs down beautifully. I should think it would get you through a few chilly spring or fall nights. The price is $345, but construction and materials are impeccable and it will last you many, many years.

Sleep well!

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Filed To: Sleeping Bags
Lead Photo: courtesy, Western Mountaineering