Dual time zones (GMT)11:42 am
A Dual Time Zone watch is one which displays the time in two time zones at the same time. The second time zone is displayed using an additional hour hand. Dual time zone watches are also referred to as GMT watches and many watches have “GMT” written on the dial to indicate that they are dual time zone watches.
The international time system divides the world into 24 time zones, and a place is assigned a time zone based on its longitude. Greenwich in London has the longitude of 0 degrees, thus making it the base point on the world time zone scale. Thus it is called Greenwich Mean Time. Other time zones are specified as their difference in hours from the Greechwich time, like GMT + 1 or GMT – 1. For example, Madrid is in the time zone immediately after London and therefore is in the GMT + 1 time zone. So, if it is 7am in London, the time will be 8am in Madrid.
GMT watches were initially introduced for pilots. While in the air, pilots need to check the local time in the place they are flying through. Since time zones are specified in terms of the difference with the GMT time, it is useful to be able to instantly check the current GMT time and thus quickly calculate the local time of the place. All the time, the pilot can of course know the local time at home on his watch.
GMT watches have an additional hour hand which points towards a 24 hour scale. Though they are called as GMT watches, the additional hand can be set to any time zone in the world depending on the requirement of the wearer. The time in the second time zone can be checked by looking at the additional hour hand and the regular minute hand. GMT watches must feature a 24 hour scale by definition so as to avoid confusion between am and pm in the second time zone.
Some dual time zone watches feature an additional hour hand yet do not have a 24 hour scale. These watches cannot be labelled as GMT watches, though they are dual time zone watches and effectively show the time in two different time zones. Dual Time Zone watches are greatly useful for frequent travellers who regularly need to check the local time as well as the time at home. They are also used by people who do business with people in other countries and need to know the time in that time zone.
GMT watches are produced by major watchmakers around the world including Rolex, Omega, Carl F. Bucherer and many others. Breitling, known for its aviation watches, also produces stunning time tellers with a GMT complication. If you are a frequent flyer or need to keep track of time somewhere else in the world, invest in a GMT watch and enjoy the convenience of viewing two time zones at the same time.