There Are Pandas, and Then There Are Pandas.
And this isn't either of them! The Pandas we're talking about here, are watches, not bears. And what got me thinking about them (again) was a link posted this morning by @cm.rook who pointed a few of us to the very attractive (and not terribly priced) Yema "Rallygraph" Panda which, in it's most traditional arrangement, looks like the one on the left, but can also be had in the version on the right: The model on the left is a true Panda, while the model on the right is called a reverse Panda. The reason for that distinction is clear--Panda bears, only come in the first arrangement. Now at this point, everyone should be thinking about the most well-know Panda, The Rolex Panda, which is actually a Daytona, and among Rolex Daytonas, the most famous of which is the Paul Newman Daytona, which was famous first, because it was Paul's, and second because it sold at auction for $17.8 million (US Dollars). The story of that auction is well-known so I'll only...
Nov 8, 2019
https://www.youtube.com/watch?v=eyggAJJuN_I
They attempt to connect in the early a.m., when the reception is best, usually two attempts. If a connection cannot be had, they wait until the next night. So if the watches are in a region with supported transmitters, and as long as you don't keep them in a basement or a radio-opaque Faraday cage, they are perfectly accurate and self-correcting.
It's only when you are out of range for a long period of time, and the core quartz watch is on its own, that the monthly error is a factor.
The annoying thing about them is when you first get one, or when you change time zones, and you want immediate sync, and you end up doing a little dance and holding it up in the air and pushing the sync button and so on, and it for some reason is unable to connect and sync. You can manually set the time, however.
https://www.youtube.com/watch?v=Mlo1pqg5adY
At any rate, all these websites, apps, phones, and radio transmitters have network latency that the software tries to estimate and correct for, but nothing is showing exact time, atomic or otherwise, although all of them are accurate enough for setting a second hand.