A zone is a rule set, not a fixed number
America/New_York and Europe/London are IANA identifiers. They describe regional rules over time. UTC−05:00 or UTC+01:00 is only an offset at a particular instant. Time-zone abbreviations are not unique worldwide, so keep the IANA identifier when communicating a location.
New York uses UTC−05:00 in standard time and UTC−04:00 during daylight saving. London uses UTC+00:00 and UTC+01:00. Their clock changes do not always occur in the same week. In 2026, New York at noon on March 10 corresponds to London at 16:00; noon on March 31 corresponds to 17:00. Check the actual date in the converter.
Some clocks skip or repeat a local time
| New York local input | Interpretation |
|---|---|
| 2024-03-10 02:30 | Missing during the spring jump |
| 2024-11-03 01:30 at UTC−04:00 | First occurrence: 05:30 UTC |
| 2024-11-03 01:30 at UTC−05:00 | Second occurrence: 06:30 UTC |
A local date and time therefore does not always identify exactly one instant. Reject skipped times; ask for an offset when a time repeats. A selected calendar day can have 23 or 25 elapsed hours, so an accurate meeting timeline must not assume 24 equal hourly positions every day.
Fractions of an hour and date changes
Kathmandu uses UTC+05:45. Adelaide uses UTC+09:30 in standard time and UTC+10:30 during daylight saving. A converter must support these minute offsets rather than round them to whole hours.
At 2026-12-31 23:30 in Kathmandu, Adelaide reads 2027-01-01 04:15. The year changes in the destination even though both clocks show the same instant. Always communicate a date as well as an hour.
Plan meetings using the whole duration
The meeting planner turns each city’s working periods into absolute intervals, then checks the entire proposed meeting against those intervals. A convenient start alone is insufficient. Weekends and crossing midnight can change a result; work-hour suitability is not a claim about a participant’s real availability.
For a future recurring event, preserve the region’s zone and its intended local time. Future governments can change rules, and browser time-zone data may lag new decisions. This site uses available browser rules and device time; it does not provide official legal time guarantees.