Following the extreme cold weather brought about by Winter Storm Jonas (or whatever you want to call it), iPhone owners, including several here at Motherboard, have noted a handful of problems with their device, including random shutoffs and a glacially slow user interface.
Luckily, while these hiccups are annoying—Evan Rodgers, Platform Manager for the VICE Growth Team, lost two snaps because his iPhone turned off in the cold—they're not likely indicative of serious damage to your device, but can do some temporary damage.
Apple's own guidelines recommend that iPhone owners keep their device in areas where the ambient temperature is between 32 degrees and 95 degrees Fahrenheit. Operating the iPhone in below-freezing temperatures, as much of the northeastern US experienced during the storm, can temporarily shorten battery life or even cause the device to shut off entirely, Apple notes. There's a reason for this.
Battery University, a clearinghouse of battery information intended for engineering students, notes that, "like humans, batteries function best at room temperature." Prolonged exposure to cold temperature "increases the internal resistance and lowers the capacity" of the iPhone's battery.
In something closer to plain English, the cold slows the conversion of the battery's stored chemical energy into electrical energy—a battery operating at 0 degrees Fahrenheit delivers only 50 percent capacity of what it would deliver when operating at 80 degrees Fahrenheit. Next thing you know your phone is dead, all because the cold put a stranglehold on your battery.
The cold similarly does a number on the iPhone's LCD display, but instead of slowing the speed of a chemical reaction, it slows down the movement of the liquid crystals. That's why LCD displays appear to smear or ghost when exposed to the extreme cold.
The best way to prevent these annoyances, then, is to keep your iPhone as warm as possible when venturing forth outside in the winter. That can be as simple as keeping your iPhone inside your pocket. There are also specialized cases that insulate the iPhone from cold.
Or, failing that, you could move to Miami, which sounds very tempting to me right now.