Short answer:
GMT stands for Greenwich Mean Time and refers to a watch’s ability to track multiple time zones simultaneously using an additional hour hand.

The Origins of GMT

Greenwich Mean Time originated from the Royal Observatory in Greenwich, England and became the global reference point for time zones.

Why GMT Watches Were Created

GMT watches were originally designed for pilots who frequently traveled across time zones. They allowed the wearer to track both local time and a second time zone.

How a GMT Watch Works

A GMT watch typically has:

• A fourth hand that circles the dial every 24 hours

• A rotating 24-hour bezel or scale

• Independent adjustment for local time

These features allow the wearer to quickly read two different time zones.

Famous GMT Watches

One of the most famous GMT watches ever produced is the
Rolex GMT-Master II, originally developed for international airline pilots.