How do time zones work? (2024)

FAQs

How do time zones work? ›

As Earth rotates on its axis, it moves about 15 degrees every 60 minutes. After 24 hours, it has completed a full rotation of 360 degrees. The scientists used this information to divide the planet into 24 sections or time zones. Each time zone is 15 degrees of longitude wide.

Time zones consist of a group of 24 spaces between lines of longitude that determine the local time between the lines. Lines of longitude are imaginary lines that travel north to south along the Earth. There is an hour difference between time zones, so the 24 times zones add up to the 24 hours in a day.

Ideally, time zones would be slices of Earth's surface 15 degrees of longitude wide that keep the same time. However, some countries and parts of countries have decided that being within a specific time zone is not preferable and have chosen offsets of 30 minutes or even 45 minutes.

If your watch says 12:00 Noon and you are in New York, which is in the EST Time Zone, you need to set your watch back one hour to 11:00 AM if you are traveling to Chicago in the CST Zone, two hours to 10:00 AM if you are traveling to Denver in the MST Zone, and three hours to 9:00 AM if you are raveling to San ...

Daylight Saving Time Today

Today, most Americans spring forward (turn clocks ahead and lose an hour) on the second Sunday in March (at 2:00 A.M.) and fall back (turn clocks back and gain an hour) on the first Sunday in November (at 2:00 A.M.).

Time zones were created because of Earth's rotation. The sun illuminates the Earth, but only one portion at a time. Since the sun can't rise in every part of the world at once, time zones maintain logical order and regulate day and night across the globe.

The country that is furthest behind in time is American Samoa, an unincorporated territory of the United States. It is located in the Pacific Ocean and is part of the U.S. territory of Samoa. American Samoa observes the time zone known as "UTC-11," which is 11 hours behind Coordinated Universal Time (UTC).

Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because it is convenient for areas in frequent communication to keep the same time. Each time zone is defined by a standard offset from Coordinated Universal Time (UTC).

No country, or part of a country, is 24 hours ahead of any part of the contiguous 48 states of the U.S. However, there are places that are 24 hours ahead of American Samoa (UTC-11) and Hawaii (UTC-10). Places that are 24 hours ahead of American Samoa are…

You can see that the most extreme time zones are +14 hours at Line Islands (Kiribati), and -12 hours in and around Baker Islands (US). Therefore, the maximum possible difference between times on Earth is 26 hours. That means that at 11:00 PM of a Monday in Baker Island, it is 1:00 AM of a Wednesday in Line Islands.

Which time zone is the most ahead? ›

Kiribati – pronounced Kiribas – is the only nation on Earth to permanently trespass into GMT+14: the earliest time zone in the world. You can think of Kiribati as the eternal land of tomorrow: if it's Sunday where you are, it's probably Monday in Kiribati.

Key Takeaways. Flying westward around the Earth's equator at over 1,000 miles (1,600 kilometers) per hour allows you to chase noon around the world, keeping the time on your watch between 12:00 noon and 1:00 p.m. as long as you maintain speed and direction.

Imagine if the entire Earth had a single time zone. Noon would be the middle of the day in some places, but it would be morning, evening, and the middle of the night in others. Since different parts of Earth enter and exit daylight at different times, we need different time zones.

Flying east or west makes a difference to jet lag

Your circadian rhythm (body clock) is less confused if you travel westward. This is because travelling west 'prolongs' the body clock's experience of its normal day-night cycle (the normal tendency of the body clock in most of us is slightly longer than 24 hours).

Time zones' boundaries are perfectly vertical lines (north to south).

Facts dependent on the IDL

According to the clock, the first areas to experience a new day and a New Year are islands that use UTC+14:00. These include portions of the Republic of Kiribati, including Millennium Island in the Line Islands.

As this US time zone map indicates, although time zones are approximately dictated by longitude, the time zones are not split exactly along longitude lines; if they were, each time zone line would be completely straight. Instead, time zone lines often follow geographic features like mountains and rivers.

Kiribati – pronounced Kiribas – is the only nation on Earth to permanently trespass into GMT+14: the earliest time zone in the world. You can think of Kiribati as the eternal land of tomorrow: if it's Sunday where you are, it's probably Monday in Kiribati.