As a warm sleeper I would absolutely die in a 15 degree bag if it's 30+ out. I would have to fully unzip it and then struggle to regulate temperature all night. The Nemo gills help a little but they do not help enough if you're a warm sleeper and it's 15 degrees over your bag rating.
I have a Nemo 35 degree bag that I use and I've never been cold in it even though the comfort rating is 40. If it's 50+ degrees out it gets too hot. 35-50 is definitely the sweet spot for it.
Personally, as long as you're not in dangerously cold conditions, I'd always go with a warmer bag and wear extra layers to bed or have a backup quilt to throw over it in case it actually gets too cold. I've had way more camping nights ruined from having a bag that's too hot than one that's too cold. You can always add layers but once you have to fully unzip your bag because it's too hot you're in a tricky place with temperature regulation for the night.
If you're a hot sleeper do not buy a 15 degree bag if you're basically only camping above 30 degrees. I would be looking at a 35 and then also buying a cheap synthetic camp blanket as an extra layer when needed or an only layer for nights that are 50+
This. I hate mummy bags. I move too much in my sleep. My Nemo takes up a bit more space in my pack but it is so comfortable and a good night’s sleep, where I can fully roll around in my bag, is worth it. I will never go back to a mummy bag.
Svafree88
