My watch automatically calibrates itself daily to a clock in Colorado. Since my watch is at least three years old, I figured that this new DST schedule would screw it up. It didn't. How do it know?!
I figured that the Colorado clock just broadcast GMT and local clocks adjusted accordingly. This new information leads me to believe that the Colorado broadcast is far more sophisticated.
It's all in the little computer chip, shuto!
I have a clock radio in my bedroom that sets its time automatically. It didn't pick up the change in daylight savings time.