When it is 09:00 in Chicago it is 00:00 in Seoul in January and 23:00 in July. Seoul is 15 hours ahead Chicago right now — but it is not constant: the difference is 15 hours ahead in January and 14 hours ahead in July. This page gives the live times in both cities, the overlap between their working days, the daylight saving dates that move the difference, and the best meeting windows.
Try the tool: Time Zone Converter — convert any time between Chicago and Seoul, with the offset for the date you pick.
Live times in Chicago and Seoul
The two cities side by side. The January column uses the winter offsets (Chicago UTC−06:00, Seoul UTC+09:00); the July column uses the summer offsets (Chicago UTC−05:00, Seoul UTC+09:00).
| Time in Chicago | Seoul in January | Seoul in July |
|---|---|---|
| 00:00 | 15:00 | 14:00 |
| 06:00 | 21:00 | 20:00 |
| 09:00 | 00:00 | 23:00 |
| 12:00 | 03:00 | 02:00 |
| 15:00 | 06:00 | 05:00 |
| 17:00 | 08:00 | 07:00 |
| 21:00 | 12:00 | 11:00 |
The world clock shows the current time in both cities live, and the individual city pages — time in Chicago and time in Seoul — explain each city's time zone, offsets and daylight saving in full.
The time difference between Chicago and Seoul
The difference is not constant. In January Seoul is 15 hours ahead Chicago; in July it is 14 hours ahead Chicago. The difference changes on Sunday, 8 March 2026 (from 15 hours ahead to 14 hours ahead) and Sunday, 1 November 2026 (from 14 hours ahead to 15 hours ahead) — those are the dates when one of the two cities changes its clocks and the other does not, or when they change on different days. Between those dates the difference is one value; outside them it is the other.
To convert a time, add the difference: 09:00 in Chicago is 00:00 in Seoul in January and 23:00 in July; 17:00 in Chicago — the end of the working day — is 08:00 in Seoul in January and 07:00 in July. To go the other way, subtract it: 09:00 in Seoul is 18:00 in Chicago in January. The time difference calculator does the arithmetic for any date, and the UTC to Seoul page gives the full conversion table for Seoul.
Meeting overlap between Chicago and Seoul
The overlap is the hours when both cities are in their working day (09:00–17:00 local time). The table marks the overlapping hours in Chicago's working day and shows what time they are in Seoul.
January
| Chicago time | Seoul time | Both working? |
|---|---|---|
| 09:00 | 00:00 | No |
| 10:00 | 01:00 | No |
| 11:00 | 02:00 | No |
| 12:00 | 03:00 | No |
| 13:00 | 04:00 | No |
| 14:00 | 05:00 | No |
| 15:00 | 06:00 | No |
| 16:00 | 07:00 | No |
July
| Chicago time | Seoul time | Both working? |
|---|---|---|
| 09:00 | 23:00 | Yes |
| 10:00 | 00:00 | Yes |
| 11:00 | 01:00 | Yes |
| 12:00 | 02:00 | Yes |
| 13:00 | 03:00 | Yes |
| 14:00 | 04:00 | Yes |
| 15:00 | 05:00 | Yes |
| 16:00 | 06:00 | Yes |
In January the overlap is 0 hours: there is no hour when both cities are in their working day. In July it is 8 hours: 09:00, 10:00, 11:00, 12:00, 13:00, 14:00, 15:00, 16:00 Chicago time. The meeting planner finds the overlap for any two cities and any date, and the meeting time finder finds it for a whole team.
Daylight saving in Chicago and Seoul
Chicago observes daylight saving: in 2026 the clocks go forward on 8 March 2026 and back on 1 November 2026, moving the offset from UTC−06:00 to UTC−05:00.
Seoul does not observe daylight saving, so its offset of UTC+09:00 never changes.
The difference changes on Sunday, 8 March 2026 and Sunday, 1 November 2026 in 2026. On those dates, one city changes its clocks and the other does not — or they change on different days — so the difference moves by an hour. A standing meeting set in one city's local time will land an hour early or late on the other side until the second city catches up. The fix is to set the calendar event in UTC, or to check the overlap again after each change. The individual DST pages — Chicago DST 2026 and Seoul DST 2026 — give the exact dates for each city.
Best meeting windows
In July the best windows are 09:00–17:00 in Chicago (23:00–07:00 in Seoul) — the same logic, with the July offsets.
Calling and travel notes
When it is 09:00 in Chicago it is 00:00 in Seoul in January; when it is 12:00 in Chicago it is 03:00 in Seoul; when it is 17:00 in Chicago it is 08:00 in Seoul. The difference is 12 hours or more, so the two cities are on different dates for part of the day: when it is Monday morning in Chicago, it is still Sunday in Seoul if Seoul is behind, or already Monday evening if it is ahead. Always state the date as well as the time when you schedule across this pair. Scheduling between the Americas and Asia is the hardest case in time-zone work: the difference is 12 hours or more, so one side's working day is the other's night. The only workable approach is to meet at the edge of the day — early morning in Chicago and evening in Seoul, or the reverse — and to keep the meeting short. Rotate the awkward hour week by week, or the same side will always be the one giving up its evening. Record the meeting and share notes, so the side that could not attend can still follow the decision.
Worked conversions
Six conversions, for January (offsets Chicago UTC−06:00, Seoul UTC+09:00):
| Chicago | Seoul |
|---|---|
| 08:00 | 23:00 |
| 09:00 | 00:00 |
| 12:00 | 03:00 |
| 14:00 | 05:00 |
| 17:00 | 08:00 |
| 20:00 | 11:00 |
In July, add 1 hour to each Seoul time. For the reverse direction, see Seoul to Chicago time.
Chicago and Seoul at a glance
| Fact | Chicago | Seoul |
|---|---|---|
| Country | United States | South Korea |
| Region | Americas | Asia |
| IANA time zone | America/Chicago |
Asia/Seoul |
| Standard offset | UTC−06:00 | UTC+09:00 |
| Daylight saving offset | UTC−05:00 | — does not observe |
| Offset in January 2026 | UTC−06:00 | UTC+09:00 |
| Offset in July 2026 | UTC−05:00 | UTC+09:00 |
| Observes daylight saving | Yes | No |
The table is the whole pair in one place. The two numbers that matter most are the January and July offsets: if they are the same in both columns for a city, that city's offset never changes; if they differ, the city observes daylight saving and the difference between the cities moves with it. The individual city pages — time in Chicago and time in Seoul — explain each city's time zone, and the DST pages — Chicago DST 2026 and Seoul DST 2026 — give the exact change dates.
Frequently asked questions
What is the time difference between Chicago and Seoul?
Seoul is 15 hours ahead Chicago right now. In January the difference is 15 hours ahead and in July it is 14 hours ahead — it changes with daylight saving.
How do I schedule a recurring meeting between Chicago and Seoul?
Pick a time inside the overlap — the edge of the day, since there is no overlap — and set the calendar event in UTC so it moves correctly when the clocks change. Re-check the overlap in March and October, when the difference moves, and rotate the time if the meeting falls outside someone's working day.
What time is it in Seoul when it is 09:00 in Chicago?
It is 00:00 in January and 23:00 in July. The time zone converter gives the answer for any date.
What is the best time for a meeting between Chicago and Seoul?
There is no hour inside both working days. Meet at the edge of the day — early morning in one city, evening in the other — and rotate the awkward hour.
Does the time difference between Chicago and Seoul change during the year?
Yes. It changes on Sunday, 8 March 2026 and Sunday, 1 November 2026 in 2026, when one city changes its clocks and the other does not.
What time is it in Chicago when it is 09:00 in Seoul?
It is 18:00 in January and 19:00 in July. See Seoul to Chicago time for the full comparison from Seoul's side.
What are the time zones of Chicago and Seoul?
Chicago is in America/Chicago (UTC−06:00 standard time) and Seoul is in Asia/Seoul (UTC+09:00 standard time).
What time is it in Chicago when it is midnight in Seoul?
It is 09:00 in Chicago in January and 10:00 in July — the same day, because Chicago is ahead of Seoul. Midnight conversions are the ones that most often land on the wrong date, so always check the date as well as the time.
Sources
- IANA Time Zone Database, via Node.js Intl (
Intl.DateTimeFormatwithtimeZone) — offsets, daylight saving dates and local times in this article were worked out from the IANA database, not typed from memory. - TimeFlow's own time-zone data (
data/cities.ts,data/dst.ts), computed from the IANA database. - TimeFlow's time zone converter and meeting planner — the live tools behind the numbers on this page.
- Time-zone and daylight saving rules are set by governments and can change. For flights, deadlines and meetings that cannot move, confirm the time with an official source.