Today the company I was doing work for asked me to audio record part of it. To do the recording I turned to the Voice Memo app on my iPhone, which has always served me well for things like this. One portion of the job involved driving in an enclosed, unheated golf cart from one building to another, and then backtracking to the start ten minutes later. Including walking time, each leg took about two minutes in a brisk (25°Fahrenheit) temperature.
I came home and sent an email to the company, then turned to Google to research what might have caused the problem. Much to my surprise, I found out that Apple suggests 32° Fahrenheit as the lowest operating ambient temperature.
My phone didn't work because of the cold weather. It's more of a weather weakling than I am!