Enjoying EarthSky? Subscribe.

123,582 subscribers and counting ...

By in
| Astronomy Essentials on Mar 11, 2012

How do I translate Universal Time into my time?

The Earth has 24 time zones. This article explains how to translate UTC to your local time zone.

The world is divided up into about 24 time zones. We say about because some states, regions or countries shift their times by half an hour from the strict 24 hour divisions. Standard time within most time zones is an integral number of hours offset from a time scale called Coordinated Universal Time (abbreviated UTC), maintained by a large number of very precise “atomic clocks” at laboratories around the world, including the U.S. Naval Observatory. For nontechnical purposes, we can presume that Coordinated Universal Time (UTC) is the same as Greenwich Meridian Time (GMT), although their exact definitions differ.

Click here to expand image above

To translate UTC into your local time, use the following table:

United States
|Atlantic Daylight Time|>. subtract 3 hours from UTC|
|Atlantic Standard Time|>. subtract 4 hours from UTC|
|Eastern Daylight Time|>. subtract 4 hours from UTC|
|Eastern Standard Time|>. subtract 5 hours from UTC|
|Central Daylight Time|>. subtract 5 hours from UTC|
|Central Standard Time|>. subtract 6 hours from UTC|
|Mountain Daylight Time|>. subtract 6 hours from UTC|
|Mountain Standard Time|>. subtract 7 hours from UTC|
|Pacific Daylight Time|>. subtract 7 hours from UTC|
|Pacific Standard Time|>. subtract 8 hours from UTC|
|Alaska Daylight Time|>. subtract 8 hours from UTC|
|Alaska Standard Time|>. subtract 9 hours from UTC|
|Hawaii-Aleutian Standard Time|>. subtract 10 hours from UTC|
|Samoa Standard Time|>. subtract 11 hours from UTC|

Europe/Middle East
|Greenwich Mean Time|>. same as UTC|
|British Summer Time|>. add 1 hour to UTC|
|Central European Time|>. add 1 hour to UTC|
|Central European Summer Time|>. add 2 hours to UTC|
|Eastern European Time|>. add 2 hour to UTC|
|Eastern European Summer Time|>. add 3 hours to UTC|
|Charlie Time (Mid East)|>. add 3 hour to UTC|
|Delta Time (Mid East)|>. add 4 hour to UTC|

Australia
|Western Standard Time|>. add 8 hours to UTC|
|Western Summer Time|>. add 9 hours to UTC|
|Central Standard Time|>. add 9:30 hours to UTC|
|Central Summer Time|>. add 10:30 hours to UTC|
|Eastern Time|>. add 10 hours to UTC|
|Eastern Summer Time|>. add 11 hours to UTC|

Asia and Africa time zones

Examples of how to convert from UTC to your local time

Let’s say you live in Houston, Texas, which is in Central Standard Time (U.S.). To convert 18 UTC into your local time, subtract 6 hours, to get 12 CST. During daylight saving (summer) time, you would only subtract 5 hours, so 18 UTC would convert to 13 CDT.

Or, let’s say you’re in Paris, France, which is in Central European Time. To convert 18 UTC into your local time, add 1 hour, to get 19 CET. In summer, add 2 hours to get 20 CEST.

When converting zone time to or from UTC, dates must be properly taken into account. For example, 10 March at 02 UTC is the same as 9 March at 21 EST (U.S.).

The table can also be used to determine the difference between the time observed in any two zones. For example, the table shows that Eastern Standard Time is three hours ahead of Pacific Standard Time (U.S.).

Bottom line: The Earth has 24 time zones, but when astronomers mention a time, it’s often “Universal Time.” This article explains how to translate Universal Time, or UTC, to your local time zone.