Below 0 C? Freezing doesn’t mean dangerous (obviously it’s dangerous if you’re homeless or don’t have regular access to heat). I live somewhere now that it hovers around freezing all winter and I literally can’t wear my old thick coats from where I grew up (northern US). I have to wear a fall coat pretty much all winter or I overheat. Below 0 F is a much better indication of dangerous weather than the freezing point.