>>1454284It's not really about your sleeping bag limit but your insulation. The main point of your sleeping bag is to keep the generated heat in, not preventing it's loss. So get a really good sleeping pad, ideally inflatable since air is pretty good insulation or at least with good R-value.
If you got that covered and really have to push your sleeping bag limit I would probably get a sleeping bag liner. Another good idea is investing into your base layer, wear a good hat and have a warm dinner before you go to sleep.
