As The Engineer explains it your alarm clock is going to betray you! They are tinkering with the power grid delivery and clocks attached to the wall, or coffee maker, or stove, or microwave may go bonkers on you. Run too fast and compound that error. Your phone and computer will be okay timewise. Those areas of the country which rely on solar and wind might have more problems. The problem is probably going to be worse out West. The article is here.