I have a dozen or more clocks and watches that set themselves by the atomic clock's WWVB radio signal. All set themselves without incident, except one I have in the garage. It caught the signal the next night.
The WWVB signal broadcasts at 60khz with one bit of data every second, with the data indicated by the bit placement in the 60 second minute, telling the year, day of year, hour, minute, second, and flags that indicate the status of Daylight Saving Time, leap years, and leap seconds. All time is UTC. A clock using an algorithm basing the DST on the date rather than the state of the DST bits would be unusual programming.
Here's the format of the time code signal
A good reference site.