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The UTC offset is the difference in hours and minutes between Coordinated Universal Time (UTC) and the standard time at a particular place. This difference is expressed with respect to UTC and is generally shown in the format ±[hh]:[mm], ±[hh][mm], or ±[hh]. So if the time being described is two hours ahead of UTC (such as in Kigali, Rwanda [approximately 30° E]), the UTC offset would be "+02:00", "+0200", or simply "+02".
By convention, every inhabited place in the world has a UTC offset that is a multiple of 15 minutes but the majority of offsets are stated in whole hours. There are many cases where the national standard time uses a UTC offset that is not defined solely by longitude.
Time zones and time offsets
A time zone is a geographical region in which residents observe the same standard time. Although nominally a new time zone is established every 15 degrees east or west of the prime meridian (meaning a one-hour change in the time), in practice local geographical or political considerations may vary its application. The most extreme example of this is time in China, which applies a single standard time offset of UTC+08:00 (eight hours ahead of Coordinated Universal Time), even though China spans five geographical time zones.
The UTC offset (or time offset) is an amount of time added to Coordinated Universal Time (UTC) time to specify the time at a given location.
Daylight saving time
Several regions of the world use daylight saving time (DST) and the UTC offset during this season is typically obtained by adding one hour to local standard time. Central European Time UTC+01:00 is replaced by Central European Summer Time UTC+02:00, and Pacific Standard Time UTC−08:00 is replaced by Pacific Daylight Time UTC−07:00.
Illustrative examples
| Location | Longitude | UTC offset | When UTC time is 12:00, local time is: | When local time is 12:00, UTC time is: |
|---|---|---|---|---|
| Accra, Ghana | 0° 12' W | UTC+00:00 | 12:00 | 12:00 |
| Mogadishu, Somalia | 45° 20′ E | UTC+03:00 | 15:00 | 09:00 |
| Dhaka, Bangladesh | 90° 23′ E | UTC+06:00 | 18:00 | 06:00 |
| Koror, Palau | 134° 29′ E | UTC+09:00 | 21:00 | 03:00 |
| Suva, Fiji | 178° 27′ E | UTC+12:00 | 00:00 | 00:00 |
| Honolulu, United States | 157° 51' W | UTC−10:00 | 02:00 | 22:00 |
| Guatemala City, Guatemala | 90° 32' W | UTC−06:00 | 06:00 | 18:00 |
| Brasília, Brazil | 47° 53' W | UTC−03:00 | 09:00 | 15:00 |
See also
- ISO 8601 – international standard for representing dates and times.
Notes
- For example, Iceland (capital Reykjavík, 22° W): the "UTC offset defined solely by its longitude" is UTC−02:00, but the national standard time uses an offset (+00:00) that differs from it.
References
- Kornberg, Sara. "Understanding UTC Offsets". Time and Date. Retrieved 2024-12-10.
External links
- time.gov (US)
- Time Service Dept., U.S. Naval Observatory Archived 2015-08-01 at the Wayback Machine
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This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources UTC offset news newspapers books scholar JSTOR December 2024 Learn how and when to remove this message It has been suggested that this article be merged into Coordinated Universal Time Discuss Proposed since December 2024 The UTC offset is the difference in hours and minutes between Coordinated Universal Time UTC and the standard time at a particular place This difference is expressed with respect to UTC and is generally shown in the format hh mm hh mm or hh So if the time being described is two hours ahead of UTC such as in Kigali Rwanda approximately 30 E the UTC offset would be 02 00 0200 or simply 02 By convention every inhabited place in the world has a UTC offset that is a multiple of 15 minutes but the majority of offsets are stated in whole hours There are many cases where the national standard time uses a UTC offset that is not defined solely by longitude Time zones and time offsetsWorld map of current time zones A time zone is a geographical region in which residents observe the same standard time Although nominally a new time zone is established every 15 degrees east or west of the prime meridian meaning a one hour change in the time in practice local geographical or political considerations may vary its application The most extreme example of this is time in China which applies a single standard time offset of UTC 08 00 eight hours ahead of Coordinated Universal Time even though China spans five geographical time zones The UTC offset or time offset is an amount of time added to Coordinated Universal Time UTC time to specify the time at a given location Daylight saving time Several regions of the world use daylight saving time DST and the UTC offset during this season is typically obtained by adding one hour to local standard time Central European Time UTC 01 00 is replaced by Central European Summer Time UTC 02 00 and Pacific Standard Time UTC 08 00 is replaced by Pacific Daylight Time UTC 07 00 Illustrative examplesExamples of the difference between local standard time and UTC Location Longitude UTC offset When UTC time is 12 00 local time is When local time is 12 00 UTC time is Accra Ghana 0 12 W UTC 00 00 12 00 12 00Mogadishu Somalia 45 20 E UTC 03 00 15 00 09 00Dhaka Bangladesh 90 23 E UTC 06 00 18 00 06 00Koror Palau 134 29 E UTC 09 00 21 00 03 00Suva Fiji 178 27 E UTC 12 00 00 00 00 00Honolulu United States 157 51 W UTC 10 00 02 00 22 00Guatemala City Guatemala 90 32 W UTC 06 00 06 00 18 00Brasilia Brazil 47 53 W UTC 03 00 09 00 15 00See alsoISO 8601 international standard for representing dates and times NotesFor example Iceland capital Reykjavik 22 W the UTC offset defined solely by its longitude is UTC 02 00 but the national standard time uses an offset 00 00 that differs from it ReferencesKornberg Sara Understanding UTC Offsets Time and Date Retrieved 2024 12 10 External linkstime gov US Time Service Dept U S Naval Observatory Archived 2015 08 01 at the Wayback Machine This standards or measurement related article is a stub You can help Wikipedia by expanding it vte
