It has only happened once, but I doubt the phone is faulty - it instantly went from a charge in the 40% range to a 'plug in now' screen, eventually returning to

It has only happened once, but I doubt the phone is faulty - it instantly went from a charge in the 40% range to a 'plug in now' screen, eventually returning to normal with the same amount of charge once I got out of the cold. Could be that different phone models behave differently in low temperatures?