There are actually other time signals around the world.
I had a Casio wave ceptor (one with analog hands which it doesn't look like they sell anymore; I should have kept it). Anyway, looking at a model that's currently available (WV-200R, but there are 2 other models available), its manual says it gets signals from "Germany (Mainflingen), England (Anthorn), United States (Fort Collins), [and] Japan."
I was curious so I looked those up:
Mainflingen DCF77 77.5 kHz
Anthorn 60 kHz
Fort Collins WWVB 60 kHz
Japan looks like they have Mount Otakayoda 40 kHz, and Mount Hagane 60 kHz.
There are also some other countries that have time broadcasts (e.g. France. Anywhere else?) but not that that watch uses.
There's also a station in Shangqiu City, Henan province, China, BPC 68.5 kHz
Casio brands watches that receive all 6 stations as multiband-6, and older ones that don't have the Chinese signal as multiband-5.
The analog display, chronograph watches like WVQ-M410-7AJF are delightful ; you can switch to timer mode and the main hands show the time ticking down (yes, they move counter-clockwise), and then switch back to normal timekeeping mode and the hands will move around the dial to set to the correct time again. Obviously at great expense to battery life, but it's solar powered. Unfortunately it's Japanese Domestic Market only, so you need to order it from a place like discovery mall japan. (The WVQ has a flimsy plastic - if you're willing to pay a lot more you could spring for the OCWS7000E ). Citizen has some GPS set watches.
Radio time signals used by watches and wall clocks are all in the 60-77.6 Khz range, probably best suited to small receivers and low power - other radio time signals are higher frequency. In the US, WWVH broadcasts at 2.5MHz, 5Mhz, 10Mhz and 15Mhz.
I had a Casio wave ceptor (one with analog hands which it doesn't look like they sell anymore; I should have kept it). Anyway, looking at a model that's currently available (WV-200R, but there are 2 other models available), its manual says it gets signals from "Germany (Mainflingen), England (Anthorn), United States (Fort Collins), [and] Japan."
I was curious so I looked those up:
Mainflingen DCF77 77.5 kHz
Anthorn 60 kHz
Fort Collins WWVB 60 kHz
Japan looks like they have Mount Otakayoda 40 kHz, and Mount Hagane 60 kHz.
There are also some other countries that have time broadcasts (e.g. France. Anywhere else?) but not that that watch uses.