What Time Zone Is Seoul In?
Seoul operates on Asia/Seoul, abbreviated as GMT+9, which is currently UTC+09:00 from Coordinated Universal Time. The IANA Time Zone Database (also known as the tz database or zoneinfo) records this under the identifier Asia/Seoul. That identifier is what your phone, laptop, and every major web service uses when they display a localized time for Seoul.
The designation Asia/Seoul follows the IANA convention of naming zones after the largest city in that timezone region. This naming is geographic, not political, it reflects where the zone is observed, not which government controls it. The full record for this zone, including historical UTC offsets and past DST rule changes, is publicly available in the Wikipedia list of tz database time zones.
UTC Offset: Seoul vs. The World
The current UTC offset in Seoul is UTC+09:00. This means Seoul time is 09:00 hours ahead of Coordinated Universal Time. To quickly convert: if it's 12:00 UTC right now, it's 03:47 local time in Seoul.
Relative to other major cities: Seoul is 14 hours ahead of New York, and 9 hours ahead of London (including any DST difference currently in effect). These differences can shift by one hour during DST transitions, which occur on different dates in different regions.
Business Hours in Seoul
Standard business hours in Seoul run from 09:00 to 18:00 local time (Asia/Seoul). In UTC, that window is 00:47 to 09:47 UTC. If you're trying to schedule a call with someone in Seoul:
- From New York: the Seoul business day runs 19:47 to 04:47 New York time.
- From London: the Seoul business day runs 00:47 to 09:47 London time.
Use the hour-by-hour conversion table above for the full 24-hour breakdown.
Daylight Saving Time in Seoul
The DST indicator above shows whether Seoul currently observes Daylight Saving Time. When DST is active, clocks advance by one hour, shifting the UTC offset by +1 and changing the abbreviation (for example, from EST to EDT in New York). When DST ends, clocks fall back and the offset returns to its standard value.
Not all countries observe DST. Japan, China, India, most of Africa, and several other nations maintain a fixed offset year-round. Whether Asia/Seoul observes DST, and the exact dates of transitions, is governed by the rules stored in the IANA Time Zone Database , the same source your phone uses. The Wikipedia article on Daylight Saving Time provides a global map and country-by-country breakdown of DST observance.
Sunrise and Sunset in Seoul
Today in Seoul (37.6°N, 127.0°E), sunrise is approximately 06:04 and sunset is approximately 17:24 local time (Asia/Seoul). These times are calculated using the Spencer equation for solar declination and apply to today's date. Latitude significantly affects day length: cities near the equator see roughly 12 hours of daylight year-round, while high-latitude cities experience dramatic swings, midsummer days can exceed 20 hours near the Arctic Circle, while midwinter days shrink to under 4 hours. At 37.6° latitude, Seoul's day length varies by several hours between summer and winter solstice.
Best Time to Call Seoul from Abroad
Standard business hours in Seoul run 09:00 to 18:00 local time (Asia/Seoul). For international callers, the ideal window is 10:00 to 16:00 Seoul time : after the morning rush and before the end-of-day slowdown. In UTC, this translates to 01:47 to 07:47 UTC. Avoid calling before 09:00 or after 20:00 Seoul time, these windows fall outside acceptable business etiquette in most professional settings. If you are calling from New York,Seoul business hours correspond to 19:47 to 04:47 Eastern time. From London, that same window is 00:47 to 09:47 GMT/BST.
Seoul Time vs Major World Cities
Right now, Seoul (UTC+09:00) is offset from major business hubs as follows:
- New York: Seoul is 14 hours ahead of New York right now (UTC-05:00).
- London: Seoul is 9 hours ahead of London right now (UTC+00:00).
- Dubai: Seoul is 5 hours ahead of Dubai right now (UTC+04:00).
- Singapore: Seoul is 1 hour ahead of Singapore right now (UTC+08:00).
- Tokyo: Seoul is the same time as Tokyo right now (UTC+09:00).
- Sydney: Seoul is 2 hours behind Sydney right now (UTC+11:00).
These differences shift by one hour during DST transitions, which occur on different dates in different regions. Always verify the current offset before scheduling.
Geographic Location of Seoul
Seoul sits at 37.5660°N, 126.9784°E. Solar noon, the moment the sun reaches its highest point, occurs at approximately 11:47 local time, when the sun crosses the meridian above Seoul. The IANA timezone Asia/Seoul groups Seoul with nearby cities that share the same legal time, even if they sit at slightly different longitudes and therefore experience solar noon at slightly different moments. Zone boundaries are drawn along political borders and transportation corridors, not strict meridian lines.
Seoul: Size, Population, and Location
Seoul has a population of approximately 10,349,312 people, placing it among the world's largest metropolitan areas. The city sits at 37°33'N, 126°58'E (decimal: 37.5660°, 126.9784°),37.6 degrees north of the equator.
At 37.6° latitude, Seoul experiences moderate seasonal variation in day length, expect roughly 9-10 hours of daylight in winter and 14-16 hours in summer. Today, Seoul sees sunrise at 06:04 and sunset at 17:24 local time. The IANA timezone Asia/Seoul groups Seoul with nearby cities that share the same legal clock, even if they sit at slightly different longitudes with marginally different solar noon times.
Working Hours Overlap: Seoul and Key Partners
Seoul's standard working day (09:00–18:00 local, Asia/Seoul) translates to different hours for common international partners:
- San Francisco (America/Los_Angeles): Seoul's workday runs 16:47 to 01:47 Pacific time.
- Berlin (Europe/Berlin): Seoul's workday runs 01:47 to 10:47 Central European time.
Overlap windows, times when both cities are within 09:00–18:00, are the practical window for real-time collaboration. Use the time difference tool on this site to find the shared working window for any pair of cities.