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<h2 id="time-zones-and-time-offsets">Time zones and time offsets</h2> <p class="note">Main article: <a href="/facts/Time_zone/x5JzdlX8">Time zone</a></p> <p>A <i><a href="/facts/Time_zone/x5JzdlX8">time zone</a></i> is a geographical <a href="/facts/Region/CdM1oaR3">region</a> in which residents observe the same <a href="/facts/Standard_time/3dKMYnjM">standard time</a>. Although nominally a new time zone is established every 15 degrees east or west of the <a href="/facts/Prime_meridian/d8KLy9r2">prime meridian</a> (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 <a href="/facts/Time_in_China/IkPhNTKm">time in China</a>, which applies a single standard time offset of <a href="/facts/UTC%252B08%3a00/1rN9I1k3">UTC+08:00</a> (eight hours ahead of <a href="/facts/Coordinated_Universal_Time/2EnjfSyu">Coordinated Universal Time</a>), even though China spans five geographical <a href="/facts/Time_zones/x5JzdlX8">time zones</a>. </p><p>The UTC offset (or time offset) is an amount of time added to <a href="/facts/Coordinated_Universal_Time/2EnjfSyu">Coordinated Universal Time</a> (UTC) time to specify the time at a given location. </p> <h3>Daylight saving time</h3> <p class="note">Main articles: <a href="/facts/Daylight_saving_time/bEWvB1Rt">Daylight saving time</a>, <a href="/facts/Standard_time/3dKMYnjM">Standard time</a>, and <a href="/facts/Civil_time/DehyR1AL">Civil time</a></p> <p>Several regions of the world use <a href="/facts/Daylight_saving_time/bEWvB1Rt">daylight saving time</a> (DST) and the UTC offset during this season is typically obtained by adding one hour to local standard time. <a href="/facts/Central_European_Time/pfceJn4Y">Central European Time</a> <a href="/facts/UTC%252B01%3a00/skLayLpg">UTC+01:00</a> is replaced by <a href="/facts/Central_European_Summer_Time/TfpdD0dW">Central European Summer Time</a> <a href="/facts/UTC%252B02%3a00/eNUq15E8">UTC+02:00</a>, and Pacific Standard Time <a href="/facts/UTC%25E2%2588%259208%3a00/dE0c1fwD">UTC−08:00</a> is replaced by Pacific Daylight Time <a href="/facts/UTC%25E2%2588%259207%3a00/A2IfxDXM">UTC−07:00</a>. </p> <h2 id="illustrative-examples">Illustrative examples</h2> <p class="note">Main article: <a href="/facts/List_of_UTC_offsets/PlQuzIJg">List of UTC offsets</a></p> <p class="note">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 <a href="/facts/Equator/CjaxbVaN">equator</a> so as not to use DST.</p> Examples of the difference between local standard time and UTC<table><tbody><tr><th>Location</th><th>Longitude</th><th>UTC offset</th><th>When UTC time is 12:00,local time is:</th><th>When local time is 12:00,UTC time is:</th></tr><tr><td><a href="/facts/Accra/wm954H5w">Accra</a>, <a href="/facts/Ghana/IkUw32Ya">Ghana</a></td><td>0° 12′ W</td><td>UTC+00:00</td><td>12:00</td><td>12:00</td></tr><tr><td><a href="/facts/Mogadishu/B5DlpNob">Mogadishu</a>, <a href="/facts/Somalia/3wQYwIdS">Somalia</a></td><td>45° 20′ E</td><td>UTC+03:00</td><td>15:00</td><td>09:00</td></tr><tr><td><a href="/facts/Dhaka/8IYAkBh9">Dhaka</a>, <a href="/facts/Bangladesh/NXk4f78Y">Bangladesh</a></td><td>90° 23′ E</td><td>UTC+06:00</td><td>18:00</td><td>06:00</td></tr><tr><td><a href="/facts/Koror_(city)/0jMm76EN">Koror</a>, <a href="/facts/Palau/sYXMGPbX">Palau</a></td><td>134° 29′ E</td><td>UTC+09:00</td><td>21:00</td><td>03:00</td></tr><tr><td><a href="/facts/Suva/NCbULXd6">Suva</a>, <a href="/facts/Fiji/JU8Hs8WH">Fiji</a></td><td>178° 27′ E</td><td>UTC+12:00</td><td>00:00</td><td>00:00</td></tr><tr><td><a href="/facts/Honolulu/DF2WutFs">Honolulu</a>, United States</td><td>157° 51′ W</td><td>UTC−10:00</td><td>02:00</td><td>22:00</td></tr><tr><td><a href="/facts/Guatemala_City/nTSb65wM">Guatemala City</a>, <a href="/facts/Guatemala/MoMcSnla">Guatemala</a></td><td>90° 32′ W</td><td>UTC−06:00</td><td>06:00</td><td>18:00</td></tr><tr><td><a href="/facts/Bras%25C3%25ADlia/Jxk9MCNu">Brasília</a>, <a href="/facts/Brazil/QHkG46GL">Brazil</a></td><td>47° 53′ W</td><td>UTC−03:00</td><td>09:00</td><td>15:00</td></tr></tbody></table> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/ISO_8601/4N8kykG9">ISO 8601</a> – international standard for representing dates and times.</li></ul> <h2 id="notes">Notes</h2> <h2 id="external-links">External links</h2> <ul><li><a href="https://time.gov/">time.gov</a> (US)</li> <li><a href="http://tycho.usno.navy.mil/tzones.html">Time Service Dept., U.S. Naval Observatory</a> <a href="https://web.archive.org/web/20150801095742/http://tycho.usno.navy.mil/tzones.html">Archived</a> 2015-08-01 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Kornberg, Sara. "Understanding UTC Offsets". Time and Date. Retrieved 2024-12-10. <a href="https://www.timeanddate.com/time/utc-offsets.html" target="_blank">https://www.timeanddate.com/time/utc-offsets.html</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>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. <a href="/wiki/Iceland" target="_blank">/wiki/Iceland</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> </ol>