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(Redirected from UTC offsets) Local difference in HH:MM from UTC

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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 ±:, ±, or ±. So if the time being described is two hours ahead of UTC (such as in Kigali, Rwanda ), 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

Main article: Time zone

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

Main articles: Daylight saving time, Standard time, and Civil 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

Main article: List of UTC offsets This set of cities has been chosen to illustrate the difference between local time and UTC, because they are as close as practicable to 0°, 45°, 90°, 135° and 180° and because they are sufficiently near the equator so as not to use DST.

Examples 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	12:00
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

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

Time

Key concepts

Measurement
and standards

Chronometry	UTC UT TAI Unit of time Orders of magnitude (time)
Measurement systems	Italian six-hour clock Thai six-hour clock 12-hour clock 24-hour clock Relative hour Daylight saving time Chinese Decimal Hexadecimal Hindu Metric Roman Sidereal Solar Time zone
Calendars	Main types Solar Lunar Lunisolar Gregorian Julian Hebrew Islamic Solar Hijri Chinese Hindu Panchang Maya List
Clocks	Main types astronomical astrarium atomic quantum hourglass marine sundial watch mechanical stopwatch water-based Cuckoo clock Digital clock Grandfather clock History Timeline

Philosophy of time

Human experience
and use of time

Time in science

Geology	Geological time age chron eon epoch era period Geochronology Geological history of Earth
Physics	Absolute space and time Arrow of time Chronon Coordinate time Instant Proper time Spacetime Theory of relativity Time domain Time translation symmetry Time reversal symmetry
Other fields	Chronological dating Chronobiology Circadian rhythms Clock reaction Glottochronology Time geography

v t e Time measurement and standards
Chronometry Orders of magnitude Metrology
International standards	Coordinated Universal Time offset UT ΔT DUT1 International Earth Rotation and Reference Systems Service ISO 31-1 ISO 8601 International Atomic Time 12-hour clock 24-hour clock Barycentric Coordinate Time Barycentric Dynamical Time Civil time Daylight saving time Geocentric Coordinate Time International Date Line IERS Reference Meridian Leap second Solar time Terrestrial Time Time zone 180th meridian
Obsolete standards	Ephemeris time Greenwich Mean Time Prime meridian
Time in physics	Absolute space and time Spacetime Chronon Continuous signal Coordinate time Cosmological decade Discrete time and continuous time Proper time Theory of relativity Time dilation Gravitational time dilation Time domain Time-translation symmetry T-symmetry
Horology	Clock Astrarium Atomic clock Complication History of timekeeping devices Hourglass Marine chronometer Marine sandglass Radio clock Watch stopwatch Water clock Sundial Dialing scales Equation of time History of sundials Sundial markup schema
Calendar	Gregorian Hebrew Hindu Holocene Islamic (lunar Hijri) Julian Solar Hijri Astronomical Dominical letter Epact Equinox Intercalation Julian day Leap year Lunar Lunisolar Solar Solstice Tropical year Weekday determination Weekday names
Archaeology and geology	Chronological dating Geologic time scale International Commission on Stratigraphy
Astronomical chronology	Galactic year Nuclear timescale Precession Sidereal time
Other units of time	Instant Flick Shake Jiffy Second Minute Moment Hour Day Week Fortnight Month Year Olympiad Lustrum Decade Century Saeculum Millennium
Related topics	Chronology Duration music Mental chronometry Decimal time Metric time System time Time metrology Time value of money Timekeeper

Coordinated Universal Time (UTC)

UTC offset for standard time and Daylight saving time (DST)

Italics: historical or unofficial

180° to 90°W	−12:00 −11:00 −10:30 −10:00 −09:30 −09:00 −08:30 −08:00 −07:00
90°W to 0°	−06:00 −05:00 −04:30 −04:00 −03:30 −03:00 −02:30 −02:00 −01:00 −00:44 −00:25:21
0° to 90°E	+00:00 +00:20 +00:30 +01:00 +01:24 +01:30 +02:00 +02:30 +03:00 +03:30 +04:00 +04:30 +04:51 +05:00 +05:30 +05:40 +05:45
90°E to 180°	+06:00 +06:30 +07:00 +07:20 +07:30 +08:00 +08:30 +08:45 +09:00 +09:30 +09:45 +10:00 +10:30 +11:00 +11:30
180° to 90°W	+12:00 +12:45 +13:00 +13:45 +14:00

Time zone data sources

tz database

Lists of time zones