phone is unresponsive at low temperature, apple understand the issue.
Early adopters reports that the phone need just a few seconds to stop detecting touches in temperatures around 0 degrees Celsius or 30 degrees Fahrenheit.

Apple said in a statement that the issues appear after a rapid and quick switch from warm to a cold environment. Although, the problem is not present on all iPhone X. Apple said the issue will be resolved in the next software update.
However, Apple officially says the iPhone X and other iOS devices should be operated at ambient temperature between 0 and 35 degrees Celsius. Those who don’t adhere to the rules suffers from this issue but we hope the fix arrives quickly.