On a more serious note, if you are into high accuracy watches, as I am, you might be interested in a source of accurate time for your location.
I believe from (what I read and know) that the radio sync watches aren't your best option here, as there are certain accuracy issues with the way the sync network is designed and works. There is a good read on how the sync works here
Then there are multiple Internet web pages and services ppl use to sync their watches with:
http://time.is,
http://NIST.time.gov to name a few, etc.
I believe that the best and the most accurate one is time.is
However, for some of us who wants ultimate accuracy there is, what I believe, is better choice for the accurate time source. I am talking GPS clocks.
https://timetoolsltd.com/gps/what-is-the-gps-clock/
They use GPS satellites which fortunately placed in the space by US government to facilitate the GPS network. Every GPS satellite has atomic clock onboard keeping time as accurately as possibly by the technology of these days. The accuracy of these clocks is critical for the GPS function, but with every GPS satellite constantly broadcasting its current location and the current time this is a perfect way to know exactly what time it is.
Although there is a tiny error due to the amount of time it takes for the GPS signal to travel from the satellite to a location on Earth (at the speed of light), it is still the best way to get the accurate time.
I use this GPS clock
https://www.tindie.com/products/nsayer/gps-clock/ from Geppetto Electronics since I was referred to it by a forumite on a watch forum. Herre it is with my Citizen 0100 cal watch
It shows the time to 1/10 of a second and clock isn't just synchronizing to GPS time and then keeping it's own time, it is actually using the PPS signal from the GPS satellites to advance the seconds. This means that if you don't have a GPS signal the clock shows "NO GPS" instead of the time. Therefore, if the clock is showing the time, you know for sure it's perfectly correct.
The specs for the GPS clock say it is accurate to within 200 µs (200
microseconds) of the GPS time signal and the GPS time signal is stable, if the clock can read it. So this is IMO currently the best clock you can possibly get, if the time accuracy is your passion.
The way to use it is to film the clock with your watch and look at the time GPS clock updates the 1/10s of a second vs when your watch second hand moves. By doing this you get the accuracy estimate of your watch of 41.666ms (or better if your recording is faster than 24 fps).
And when you sync your watch, the final accuracy of the settings depends on your reaction time (which for humans is usually 150-250ms). However, you can do better, as you can
anticipate when to react to the time change as opposed to purely react to it.
