Some ordinary atomic watches will change time zones automatically while in the United States. The radio signal for atomic watch time-keeping is emitted from Boulder, Colorado and as long as the watch is within the 2,000-mile radius that the emitter covers, it will keep time regardless of the time zone. If you travel outside the United States, however, you will have change the time zone manually.
Some solar atomic watches, popular for their green power source, will change time zones automatically around the world. Casio first brought the solar atomic watch to market, and Oceanus, Citizen and Seiko soon followed the trend in 2009.
The Casio Pathfinder is a solar atomic watch. In 2010 it retailed around $450 and is a watch for true adventurers. It is extremely tough and includes a compass, thermometer, barometer and altimeter, while being water resistant to 110 yards. It also adjusts for world time zones and displays the time in both analogue and digital formats.
This Seiko solar atomic watch also adjusts for world time zones. It is a stylish dress watch which will set you back around $1,000, as of 2010. The watch is water resistant to 110 yards and its solar battery will last for up to six months when fully charged.
This solar powered world time zone watch is somewhere between the action-oriented Casio and the Seiko dress watch. Suitable for day wear and more, this watch is water resistant to 218 yards. It retails for around $599 for stainless steel, and $795 for a titanium version. Marketed as a watch for airplane pilots, its slide rule bezel feature assists with fast calculations for things like ground speed, fuel consumption, range and distance traveled.
