Hot and Cold Temperatures Are Bad for the Battery
TRUE: Both extreme heat and extreme cold are bad for batteries, but they have different effects. Heat can cause permanent damage to your battery. It’s always best to keep your phone between 62º and 72ºF (16º to 22ºC). If your iPhone is stored above 95ºF (35ºC), the software may prevent it from charging above 80% to prevent irreversible damage. When the device is in a frigid environment, the battery itself will drain quickly, but normal battery life will return once it’s in a healthy temperature. No long term damage is caused by extended periods in cold temperatures.