
NEMO
Disco 15 Series
Spacious for side sleepers; bulky, temp rating optimistic.

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I have a Nemo Jam, which is shaped like the Disco. I'm a side sleeper and I absolutely love it. I don't think I could sleep in a mummy bag.
The Nemo spoon shaped bags, TR Boost or BA Torchlight are all nice and accommodating for flamingo type sleepers (I am one as well.) Also consider a quilt!
i’m 5,3” and i have a women’s nemo bag that fits just right
I can vouch for Nemo Equipment bags (I have 3 down ones and one synthetic for different temperature ranges). I can also vouch for Marmot down coats (for in-town use not for winter backpacking or camping) but I have never used a Marmot sleeping bag. My 3-season backpacking bag is a Nemo down 15F version that is probably 10 years old now and it is great except for in extreme heat and extreme cold at night. I have an old Eddie Bauer Flying Squirrel Sleeping Bag (modified with velcro) that I use for extreme heat and other Nemo down sleeping bags for winter backpacking. Nemo has a lifetime warranty on their equipment.
Nemo down 15F is my favorite. I felt warm sleeping when outside was below 30F. Wait for the next sale in REI you can snag it for nice discount.
I love my down 15* Nemo bag. It's a huge warmth difference compared to my synthetic 25* Nemo.
Just got back from Algonquin where the temps dropped to 3 degrees C. I was comfy in my fairly new -9 degree C Nemo down bag wearing long base layers only, but I felt if it got below freezing I would need some additional layers. Other commenters are giving good advice when they say a good sleeping pad makes a big difference, especially if the ground is already cold (not just air temps dropping at night). Don't trust temp ratings of cheap bags and aim for something with a rating 15 degrees below the coldest you could expect it to possibly get.

NEMO
Disco 15 Series
Spacious for side sleepers; bulky, temp rating optimistic.
Hammock Gear
Classic Burrow 20°F
Budget king; very warm but heavier than ultralight.

NEMO
Disco 30
Spoon shape for side sleepers; prone to zipper issues.

Western Mountaineering
VersaLite
Durable, very warm; premium price, too hot in summer.

Katabatic Gear
Alsek 22°F Quilt
Versatile 3-season quilt; secure pad attachment, high price.

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Kelty - Tru.Comfort Doublewide 20
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Enlightened Equipment - Revelation APEX

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Feathered Friends - Egret UL 20/30

Ranked #1
NEMO - Disco 15 Series