I'm riding from Vancouver to Edmonton, starting in late May (and across the rest of Canada after that) but I'm not sure what kind of sleeping bag to get for those Western nights. I was walking around MEC here in Ottawa, looking at sleeping bags and realized I didn't really have a sense of what to expect out West at night. I own gear for nights down to -30 but I think that might be overkill, so what kind of rating do you all think should be good?
I know it can get cold up there during the day, so I'm bringing cold-weather gear which I'll send home once it is sure to stay warmer out. I could also send home my sleeping bag later too and pick up a really really light one instead (I'll probably end up doing that anyway because I hate the heat), so I don't necessarily have to compromise between the mountain cold and Eastern heat either.
I want something warm enough that I won't have to worry about not being warm enough wrapped up in my sleeping bag, cold clothing and emergency mylar blanket. I have a Thermarest mattress and will be sleeping in a 1-2 person, 3-season tent.