Why is there not a radio signal that sets automatic self-time changing devices like wall clocks and wrist watches for Daylight Saving Time?

Answer 1

Cannot Use Radio SignalsWall clocks and watches don't run off of radio frequencies. They rely on gears and electronic gadgets themselves, not signals. It's cheaper to make and buy them that way. I believe the Discovery channel store sells a clock that automatically changes for the time standards.

Self-adjusting clocks and watches do adjust automatically for Daylight Saving Time, but you have to have the Daylight Saving Time function turned on.