Cumulus - Panyam 600

What's your budget? And how important weight is?  I don't camp in winter but I have Cumulus Panyam 600 which is comfort rated to - 6C, and I find it great for 3 seasons. I definitely wouldn't want anything less warm for winter but I'm a woman so YMMV depending on your gender and how warm you sleep. Don't forget to get a good pad as well. 

What's your budget? If you can spend a bit I recommend Cumulus Panyam 600.

Great shout. The 600 could be better for winter if you're a cold sleeper (not so much heavier)

Cumulus pamayra 600. I’m 180/80 and very warm and comfy. I’ve used it in NZ and PCT at 0c. Other thing to consider is your sleeping pad. All bags will feel cold if it’s seeping in from below

I went with a Cumulus Panyam 600 and couldn’t be happier. Went from 1535 to 970g and also saved a ton of room (from synthetic to down). I considered using a quilt but fussing around with straps and potential drafts didn’t sound very appealing to me.

Pretty sure that bag will be overkill, plus it's heavy as hell. Look at Cumulus Bags - $19 shipping to US, last I checked. I have the X-Light 400. I sleep cold, and this bag is too warm to use zipped up above 35F. The heavier, budget equivalent would be the Panyam 450. The Panyam 600 is closer in warmth to the Bishop Pass, but it would still be overkill. You can add extra down to the Panyam 450 or X-Lite 400 to boost warmth for extra $$$. https://cumulus.equipment/us_en/sleeping-bags/down.html