A team with people in New York, London and Ho Chi Minh City sets up a weekly call at 9:00 in New York. For most of the year it lands at 14:00 in London and 20:00 or 21:00 in Vietnam. Then, for three weeks every March and one week every autumn, half the team turns up an hour early or an hour late. Nothing is broken: the countries change their clocks on different days. This article traces that call through 2026 with exact times, then looks at the two moments every year when a local time does not exist or happens twice.
All the times below were computed with the code behind our time zone converter, which uses your browser's own time zone database.
The rules, in short
- United States and Canada (most of them): clocks go forward on the second Sunday in March and back on the first Sunday in November. In 2026: 8 March and 1 November.
- European Union and United Kingdom: forward on the last Sunday in March, back on the last Sunday in October, both at 01:00 UTC. In 2026: 29 March and 25 October.
- Vietnam: no daylight saving. UTC+7 all year.
- Sydney (southern hemisphere): the other way round. Clocks go back on the first Sunday in April (5 April 2026) and forward on the first Sunday in October (4 October 2026).
The US and Europe do not change on the same day, so for a few weeks each spring and autumn the gap between them is one hour smaller than usual.
A weekly 9:00 New York call through 2026
Every row is a Monday at 9:00 in New York:
| Monday | London | Berlin | Ho Chi Minh City | Sydney |
|---|---|---|---|---|
| 2 March | 14:00 | 15:00 | 21:00 | 01:00 Tue |
| 9 March | 13:00 | 14:00 | 20:00 | 00:00 Tue |
| 16 March | 13:00 | 14:00 | 20:00 | 00:00 Tue |
| 23 March | 13:00 | 14:00 | 20:00 | 00:00 Tue |
| 30 March | 14:00 | 15:00 | 20:00 | 00:00 Tue |
| 6 April | 14:00 | 15:00 | 20:00 | 23:00 Mon |
| 19 October | 14:00 | 15:00 | 20:00 | 00:00 Tue |
| 26 October | 13:00 | 14:00 | 20:00 | 00:00 Tue |
| 2 November | 14:00 | 15:00 | 21:00 | 01:00 Tue |
Read down the columns:
- London and Berlin move by an hour for three weeks in March (9, 16 and 23 March) and one week in October (26 October), then return to normal. Those are the weeks when someone in London blocks 14:00, as usual, and finds the call already over.
- Ho Chi Minh City changes only when New York does: 21:00 in winter, 20:00 from 9 March until 1 November. Vietnam's clock never moves, so for the Vietnamese team the meeting simply shifts with the seasons of a country 12 time zones away.
- Sydney changes four times in the year: when New York springs forward (01:00 to 00:00), when Sydney falls back in April (00:00 to 23:00 on Monday, the same day as New York), when Sydney springs forward again in October, and when New York falls back. Someone in Sydney sees the meeting on a different calendar day depending on the season.
The practical rule: a recurring meeting belongs to one time zone, and everybody else's local time follows it. Decide whose 9:00 it is, write that zone down, and expect the others to move.
When a time does not exist: the spring gap
On 8 March 2026 in New York, clocks jump from 01:59:59 straight to 03:00. A time of 02:30 never happens that day. If you ask "what is 02:30 on 8 March in New York?", there is no right answer, only a convention. Our converter marks the time as skipped and moves it forward by the length of the gap, to 03:30 EDT (07:30 UTC), which is what a clock that kept running would read. In London the gap is on 29 March, from 01:00 to 02:00, so 01:30 becomes 02:30 BST.
Calendar software has to make the same choice for any event scheduled inside the gap, which is why a reminder set for 02:30 on that night fires at 03:30, or not at all, depending on the program. Avoid scheduling anything between 01:00 and 03:00 local time on change nights.
When a time happens twice: the autumn overlap
On 1 November 2026 in New York, clocks go from 01:59:59 EDT back to 01:00:00 EST. The hour from 01:00 to 02:00 happens twice. "01:30 on 1 November" is two different moments, an hour apart: 05:30 UTC (the first time, still EDT) and 06:30 UTC (the second, already EST). In London the overlap is on 25 October, where 01:30 means either 00:30 UTC or 01:30 UTC.
The converter says that the time happens twice, shows the first one, and has a switch for the second. A program that does not ask has to guess, and the usual guess is the first one. For anything that matters, a payroll cut-off, a backup window, an exam start, write the UTC offset next to the time (01:30 −05:00) or schedule it in UTC.
Common mistakes
- Storing a future meeting as a fixed UTC offset. "14:00 GMT+1" is right until 25 October and wrong after it. Store the zone name,
Europe/London, and let the software work out the offset for each date. - Assuming everyone changes on the same weekend. Europe and the US differ by two to three weeks in spring and one week in autumn; the southern hemisphere changes in the opposite direction.
- Saying "EST" in summer. New York is on EDT (UTC−4) from March to November. Writing "9:00 EST" in July is an hour off for anyone who takes it literally. "New York time" avoids the problem.
- Forgetting countries without daylight saving. Vietnam, most of Asia, most of Africa and the US state of Arizona do not change. Their offsets to everyone else still change twice a year.
- Sending invites without a time zone. A calendar file with a "floating" time shows 9:00 to everyone, wherever they are. The ICS calendar generator writes the zone into the invite; calendar invites, time zones and RRULE explains how.
Planning a meeting that works
Add the cities to the time zone converter, pick a date in the week you care about, and look at the hour grid: work hours, evenings and nights are marked for each city, so you can find the overlap at a glance. Then check the same slot in the first week of the next change period. If it still works for everyone, it will work all year.