Enviroment/Atmosphere or Village Theme
Consider a button in settings next to clan chat filter. This new button is titled "Enviroment/Atmosphere".You have the option of day, night, desert, mountain, space, rain, snow, hail, clear, apocalypse. These can be used for the chief to personalize their base. This idea might be easier to do instead of a time zone related day or night. That way the game won't have to use any gps or location add-on. These options could also be titled "Village Theme" and would be cheap to continue new ones every so often for future updates.