A time difference is not always fixed
A city’s UTC offset can change when it uses standard time or daylight time. Remembering Seoul and New York as “always 14 hours apart” can therefore be wrong around a transition. The selected date matters even when the cities stay the same.
Transition days can skip or repeat clock time
On a spring transition, some local clock times do not exist; on an autumn transition, a clock hour can occur twice. For meetings, flights, or broadcasts, verify the exact date and include the city and time zone.
Read the map with the calculation
The daylight map shows the Sun’s position at the selected instant, while each city card applies that date’s time-zone rules. They answer different questions, so check both after changing the date.
The same 22:00 in Seoul, different seasonal offsets
These examples compare the same Seoul clock time in winter and summer 2026. Holding Seoul time fixed changes New York and London local times by one hour.
| Seoul | New York | London |
|---|---|---|
| 2026-01-15 22:00 | 2026-01-15 08:00 (UTC−5) | 2026-01-15 13:00 (UTC+0) |
| 2026-07-15 22:00 | 2026-07-15 09:00 (UTC−4) | 2026-07-15 14:00 (UTC+1) |
On March 8, 2026 in New York, one elapsed hour after 01:30 is 03:30 on the local clock. On November 1, 01:30 occurs twice: once at 05:30 UTC and again at 06:30 UTC. “01:30 in New York” alone does not identify which instant is intended on the autumn transition date.
Try it on the map
- Check the city and IANA zone, such as America/New_York, instead of relying on a fixed-offset abbreviation such as EST.
- Check recurring events in winter, summer and between the regions’ transition dates. Countries do not necessarily change clocks on the same date.
- Use a calendar that accepts UTC or an explicit offset to disambiguate a repeated local time. This map’s device-local input has no first-occurrence or second-occurrence selector.
Limits to keep in mind
The service uses time-zone data supplied by your browser and operating system; it does not download the newest IANA database on every visit. If local rules recently changed, update your device and confirm the organizer’s announced time. These examples describe 2026, not transition dates in other years.
Official references
If you find an error in an explanation or example, please let us know on the contact page. Report an error