Prime Meridian Day
Prime Meridian Day sparks interest every November 1st as people celebrate the invisible line that divides the earth into the Eastern and Western Hemispheres. This day marks the significance of the Prime Meridian, an imaginary line that starts at the North Pole, runs through Greenwich, London, and ends at the...
Leverage Prime Meridian Day to drive tourism to Greenwich and position brands as connectors of global audiences through educational and experiential content.
- Stand on two hemispheres at once: a bucket-list moment for travelers
- Time zone trivia challenge: test your global knowledge
- Virtual tour of the Royal Observatory and historic Time Ball drop
- Sync your watch with Greenwich Mean Time—a nod to global precision and timekeeping
Prime Meridian Day honors the line of longitude that is recognized globally as the starting point for measuring geographical locations.
This day marks the decision made during the International Meridian Conference held in Washington, D.C., in 1884, when representatives from 25 countries chose the Greenwich Meridian as the universal zero-degree longitude.
Greenwich’s choice was influenced by its already prevalent use in shipping and navigation. It relied heavily on the charts that marked Greenwich as the prime meridian. This made it the practical choice for establishing a global standard.
Since the conference, the Prime Meridian has played a fundamental role in global navigation, timekeeping, and geographical information systems.
The celebration of Prime Meridian Day began as a way to recognize the importance of global unity in timekeeping and the contributions of the Greenwich Meridian to mapmaking and navigation technologies.
It serves as a reminder of the advancements in global communication and coordination that have been possible due to the establishment of a common longitudinal reference point.
Stand on the Line
Start by standing with a foot in each hemisphere at the Prime Meridian Line in Greenwich. It’s not every day you get to straddle the east and west of the world!
Time Ball Drop at Flamsteed House
Gather around Flamsteed House at the Royal Observatory to watch the historic Time Ball drop—an old-time method of signaling the exact time to ships on the Thames and Londoners.
Watch Adjustment
Why not synchronize your watch under the Shepherd Gate Clock? It’s the first clock to show Greenwich Mean Time to the public. A perfect chance to align yourself with global time!
Explore Time Zones
Dive into the peculiarities of time zones worldwide. It’s a great opportunity to understand why we have them and how they affect our lives, especially if you’re a fan of trivia.
A Nighttime Visit
Visiting the Prime Meridian Line after dark offers a unique view, with a symbolic green laser marking the line. Enjoy the stars and learn a bit about astronomy while you’re at it.