In my experience, 'operating temperature' on the lower end is the temperature it can be reasonably expected to turn on from being cold and powered off.
For example, the Reolink RLC-410 claims a working environment of down to -10°C, but have themselves
admitted that the cameras once powered on and warmed up are fine to operate as low as -42°C. But they also advise against using battery-powered cameras in severe weather. Batteries and cold temperatures aren't friends.