How a GMT works.
A GMT adds a fourth hand that turns once in 24 hours. Read against a 24-hour scale, it shows home time while the main hands show local time. What is a GMT watch? explains the flyer and caller types.
How a world timer works.
A world timer has a ring of city names and a 24-hour disc. Set the local city against the hour hand and the other cities line up with their times. It shows many zones at once but usually costs more and has a busier dial.
Atomic and digital world time.
Some analog-digital watches, such as the Skyhawk A-T GMT, let you choose a second city on a digital panel and use atomic synchronisation. They trade simplicity for features.
Which should you choose?
Time-zone watches we recommend.
SHY037 Titanium NH34 GMT Diver
A titanium GMT diver with a ceramic bezel and a 300 m rating
Admiral GMT Black
A titanium-bracelet GMT with a black-and-red diver profile.
Promaster Skyhawk A-T GMT Blue Dial (JY8125-54L)
The Skyhawk with a second time zone and atomic accuracy
A few good questions.
What is the difference between a GMT and a world timer?
A GMT tracks one or two extra zones with a 24-hour hand. A world timer shows many zones at once on a city ring.
Which is better for travel?
For most trips a GMT is simpler and easier to read.
Can a GMT show three time zones?
Yes, by rotating the 24-hour bezel to read a third zone.
Do I need a GMT watch?
Only if you regularly track more than one time zone; otherwise it is a good everyday watch with extra utility.
How we write guides: we explain watchmaking from manufacturer documentation and published standards, and say plainly where numbers vary by brand or movement. Our approach.