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Prime Meridian Day

It's time to mark your calendars for Prime Meridian Day - the perfect opportunity to learn about this important line that divides our planet!

Sunday

November 2026

Last updated February 7, 2026 · by the Holiday Calendar Team

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YEARLY DATENovember 1

OBSERVED INInternationally

CATEGORYCulture

SUBCATEGORYCivics

INTRO

Introduction

PHOTO

Get ready to celebrate Prime Meridian Day on November 1! This holiday commemorates the imaginary line that runs through Greenwich, England and serves as the basis for measuring longitude and dividing the world into Eastern and Western hemispheres. It was first established in 1884 at the International Meridian Conference, and since then has been a crucial tool for navigation and timekeeping. Whether you're a history buff or just curious about how our world is divided, this day is a perfect opportunity to learn more about the Prime Meridian and its significance. So mark your calendars and join in on the celebration!

TIMELINE

Prime Meridian Day Timeline

Establishment of Prime Meridian

The Prime Meridian, passing through the Royal Observatory in Greenwich, England, is formally established at the International Meridian Conference.

Adoption by Navigation Charts

Navigation charts start to officially use the Greenwich meridian as zero degrees longitude.

Universal Standard Time Reference

The Prime Meridian is officially acknowledged as the universal reference for Standard Time.

Introduction of UTC

Coordinated Universal Time (UTC), based on Greenwich Mean Time (GMT), is introduced to provide worldwide time standardisation.

Prime Meridian Centennial

The 100th anniversary of the Prime Meridian's establishment is celebrated, underlining its importance to global timekeeping and navigation.

Prime Meridian Day Instituted

Prime Meridian Day begins being celebrated annually on November 1, encouraging worldwide acknowledgement of this important geographical landmark.

GET INVOLVED

How to Celebrate Prime Meridian Day

Host a meridian-themed party

Gather your friends and family for a themed party centered around the Prime Meridian! Decorate with maps, globes, and compasses, and serve food and drinks from countries that the Prime Meridian passes through.

TAKE

Take a virtual tour along the Prime Meridian

Visit the Prime Meridian from the comfort of your own home by taking a virtual tour along its path. You can learn more about the history and significance of this imaginary line while exploring famous landmarks and cities that it passes through.

CREATE

Create a craft inspired by the Prime Meridian

Get creative and make a craft inspired by the Prime Meridian. You could make a globe, a map, or even a replica of the Greenwich Observatory, which is located at 0° longitude.

LEARN

Learn about time zones and daylight saving time

Since the Prime Meridian is the starting point for time zones, take some time to learn more about how they work and why we have daylight saving time. You can impress your friends with your newfound knowledge at your Prime Meridian Day celebration!

WATCH

Watch a movie or documentary about longitude

There are several movies and documentaries that explore the history and impact of the Prime Meridian, such as "Longitude" and "Greenwich: The Mean Time". Host a movie night and learn something new about this important line of longitude.

WHY THIS DAY MATTERS

Why Prime Meridian Day is Important

It has historical significance

The Prime Meridian was established in 1884 at the International Meridian Conference in Washington D.C., where representatives from 25 countries agreed to use it as the standard for longitude. This event marked a significant step towards international cooperation and communication, and the Prime Meridian serves as a symbol of this historic moment.

It is the basis for standard time zones

The Prime Meridian is an imaginary line that divides the Earth into Eastern and Western hemispheres. It serves as the starting point for measuring longitude, which is used to determine different time zones around the world. Without it, we would not have a standardized system of timekeeping.

It is important for navigation and cartography

The Prime Meridian is also used in navigation and mapmaking as a reference point for determining direction and location on the globe. It helps sailors, pilots, and travelers accurately plot their course and avoid getting lost. Mapmakers also use it as the central line when creating maps of the world.

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