What is a Dual Time Watch? Difference Of Dual Time and GMT

There are so many good looking watches in the world. One could say that there might be too many. Some even argue that some watches where made just, because. The dual time watches, however serves a very good purpose for the traveling businessman/woman.

A dual time watch has two subdials on the dial. Each subdial is adjusted to different time zones. The dual time watch is not to be confused with GMT watches. The GMT watch has an extra hand on the dial and 24-hour bezel.

A dual time watch is often confused with the GMT watch. If you are a bit pedantic “dual time” means two different times. A GMT and dual time will both tell you two different times at a glance. However, I am here to tell you the difference in dual time and GMT watches.

What is a Dual Time Watch?

A dual time watch is a watch that has two different faces showing two different time zones. A dual time watch is made different from a GMT watch, technically. While there is nothing wrong with calling both a GMT, as they serve the same purpose, the movements are built differently.

A dual time watch is from a technical point of view more complicated, because it has to move two subdials. If there is a main dial and a sub-dial, the subdial will be attached to the main dial, however using different sizes of gears to account for the size difference between the main dial and subdial. If the two dials have the same size, they are put in series.

The second type of dual time is very similar to the GMT. Technically a dual time zone watch with a 24-hour hand works just like a GMT when looking at the movement. However, the distinction is in the bezel, which a dual time watch does not feature.

Sinn 856 UTC Dual Time Watch
Sinn 856 UTC Dual Time Watch

Another type of dual time watch is the “invisible hour hand”. This is easily seen on a Patek Philippe Nautilus Travel Time Chronograph or a Sinn 856 UTC. Adding another hour hand to the watch makes the movement slightly less complicated to adjust time. Adjusting a dual time watch, which has an additional hour hand, is merely adjusting the hour hand, which will jump in 1-hour increments.

Dual time watches are not very popular, and hence they are rarely seen one a wrist. However, the most popular dual time watch you might have heard of is a Jaeger-LeCoultre Duoface Reverso. The Reverso has gotten a lot of attention for its dual time face. The watch has the option of flipping side, once side is your local time, and on the other side is the time you are following.

How to Read A Dual Time Watch

Dual time watches are very easy to read. If the watch is featured with two separate subdials, you simply identify the time zone you which to know the time off. If you have a 24-hour dual time watch the reading is a bit different.

First, you look at the position of the firth hand, the hour hand from the 24-hour dial. Second you identify the minutes hand. This is your time on the tracking time zone. In the picture of the Sinn, the clock is 08:09 in the 24-hour zone, and 10:09 in the local time zone.

Be aware that a dual time zone will change date according to the local time zone. Hence, if the local time zone is behind in relation to the tracking time zone, the date will not be accurate for the tracking time zone.

Who Uses Dual Time Watches?

Dual time watches are targeted travelers or people with foreign relationships such as business or family. Frequent travelers will enjoy knowing what the time is in the region of their loved once. In case they are calling from time to time, it is nice to know that they aren’t sleeping or being at work occupied in meeting.

Remote workers and people doing a lot of business travel also benefit from the dual time watches. Knowing when their colleagues start their workday is essential for communication within the business.

While pilots would benefit more from GMT watches, dual time watches have a very similar purpose and therefore might fulfill the job. The GMT watch was developed because pilots needed the local time (from take-off) and the destination time.

Lastly, enthusiasts will also want dual time watches as they are a cool piece of complication.

What Is A GMT Watches

A GMT watch tells time in two different time zones. The GMT hand shows the time in a 24-hour scale. Adjusting for a time zone change is simply rotating the bezel in + or – direction of the GMT.

Rolex developed the GMT in 1954 watch in collaboration with pilots from Pan Am, who needed a way to track time between their local time and destination. The Rolex GMT Master was developed and featured a fourth hand on the dial. GMT watches can come with internal or external bezels, fixed or rotatable. However, the GMT watch is meant to have a rotating bezel. The name GMT comes from the name Greenwich Mean Time, which we know as Coordinated Universal Time or UTC today.

The GMT watch looks like a diving watch. However, instead of 0-60 on the bezel, it is 0-24. In addition, there is added a fourth hand to the dial. The fourth hand is a 24 hour hand that is used to track the time set on according to the bezel. In simpler terms, there is the regular three hands that follow the local time and an additional fourth hand, which is set to another time zone and read from the bezel.

The idea of the rotating bezel is for pilots to simply turn the bezel either + or – depending on the direction they are going when they are about to take off. Wherever the GMT hand (the fourth hand added to the watch), and the pilot will fly 2-time zones, they rotate the bezel 2 click/hours. Now the time is adjusted to the new time zone.

How To Read A GMT Watch

To read a GMT watch, you simply identify the hand of the GMT function. The GMT hand often has a different color than the other hands telling local time. If the GMT hand is located at the 18-hours mark on the bezel, and the minute hand is located at the 15 minutes mark, the clock is 18:15. Now, if you want to trace a time zone, which is 3 hours behind, you move the bezel clockwise. Now the watch should show 15:15, instead of 18:15. This can be done in either direction using the bezel.

Some GMT watches have a colored bezel. These colors are typically red and blue. This is where the name “Rolex GMT Pepsi” name came from. The “Pepsi” name is now used as an acronym for a GMT with red and blue bezel. The color is to show the night hours and day time hours. Red from 06:00 to 18:00 (6AM – 6PM) and the blue from 18:00 to 06:00 (6PM – 6AM).

How Set A GMT Watch

The GMT watch can do some amazing tricks. While it may seem redundant in today’s world of phones and computers, you can use the GMT watch to see time between 2 or 3 time zones, and you can use it as a compass. Yeah, your phone can do that as well, but it is cooler using a watch.

How to set the GMT watch for 2 time zones.

Step 1: Set the 24-hour GMT hand to the local time based on the 24-hour scale.

Step 2: Set the hour hand to the current time on the 12-hour scale

Step 3: Now rotate the bezel to represent your second time zone. Going clockwise loses time, hence counter-clockwise gains time.

How to set the GMT watch for 3 time zones.

What is important here is that you have the zero-mark of the bezel aligned with the 12 hour at the dial.

To track 3 time zones. You must first set the GMT hand to GMT time and have the hour hand set to local time.

If the GMT time is 22 hours, and the local time is 17 hours. The GMT hand must be set to 22 hours, and the local time to 5. You can now use the bezel to represent a third-time zone. Rotating the bezel, you can quickly see the time of a third-time zone. Wanting only to track 2 time zones again? Just turn the zero-mark of the bezel to the 12-hour mark on the dial.

How to use the GMT as a compass.

This only works if you are in the northern himosphere and have both the GMT and hour hand is set to local time.

If you place the watch on a table and point the hour hand at the sun, the GMT hand will point north.

There you go, 2 or 3 time zones and even a compass.

Jonas Henriksen

AllInWatches is founded by Jonas, who has a great interest in mechanical watches. All aspects of manual and automatic (mechanical) watches is a big interest and have been a passion since 2015, where the first automatic watch was purchased. Seeing the transparent case back and discovering the heritage of watchmaking piqued an interest in horology.

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