Of course, then you get into the problem of whether you want to store that by time zone, or by actual physical location. If it's the latter, you might have to d

Of course, then you get into the problem of whether you want to store that by time zone, or by actual physical location. If it's the latter, you might have to deal with the time zone that covers that location changing at some point between now and then, like when Kazakhstan merged what were previously two separate time zones into one.