Scheduling across time zones

The best meeting time is one that falls inside everyone's working day. So the first job is to find the hours when all the cities are at work at once: the overlap.

TimeZonar's world clock does this for you. Add each person's city and its working-hours chart shows 9 AM to 5 PM in every city on one line, with the shared hours marked. Click a time in the chart to see it in every city, then use "Copy link" to send the same set of cities to everyone else.

The further apart two cities are, the smaller the overlap. On a weekday in January, with everyone working 9 to 5:

• New York and London share three hours: 9 AM to noon in New York, which is 2 PM to 5 PM in London.
• Los Angeles and London share none. When London's day ends at 5 PM, it's only 9 AM in Los Angeles.
• Los Angeles and Sydney share three hours, but on different days: 2 PM to 5 PM on Wednesday in Los Angeles is 9 AM to noon on Thursday in Sydney.
• New York, London and Bangalore have no shared hour at all. Someone will have to start early or stay late.

These numbers move during the year, because cities change their clocks on different dates, or not at all. Check the overlap for the actual date of the meeting, not today.

For widely spread teams, there's often no time that suits everyone. A few ways to handle it:

• Stretch both ends a little. An 8 AM start in New York is 1 PM in London and 6:30 PM in Bangalore. An hour early for one person and a little late for another is often better than a very bad time for one person.
• Take turns. For a regular meeting, rotate the time so the same people aren't always the ones joining at night.
• Split it. Two shorter meetings, each covering the cities that overlap, can work better than one meeting at a bad hour.
• Skip the meeting. A shared document, a recorded video or a written update lets people take part during their own day.

The working week isn't the same everywhere. Late Friday in the Americas is already Saturday in Asia and Australia, and Monday morning in Sydney is still Sunday in the US.

Weekends also fall on different days. Saudi Arabia works Sunday to Thursday, for example, while the United Arab Emirates moved to a Saturday and Sunday weekend in 2022.^[1] Ask people which days they work rather than assuming.

• Use a calendar invite. Calendar events carry a time zone with them, so each person's calendar shows the meeting in their own local time.^[2]
• Write the time in more than one zone. In the message itself, give the time in each main city, like "Wednesday 9 AM New York / 2 PM London", or in UTC. Name cities rather than abbreviations like CST, which can mean different things.
• Include the date in each city when the meeting crosses midnight for someone. "Thursday 9 AM Sydney" is clearer than leaving people to work out the day.

A recurring meeting is set in one city's time zone, usually the organizer's. When that city changes its clocks, the meeting stays at the same local time there, so it moves by an hour for anyone whose clocks didn't change on the same day.^[2]

The US changes its clocks two to three weeks before Europe in March, and one week after it in autumn.^{[3, 4]} So a 9 AM New York meeting that's usually 2 PM in London will be at 1 PM in London for those weeks. Southern hemisphere countries, like Australia, change in the opposite direction, so their gap to Europe and North America can shift by two hours across the year.

Put a note in your diary to check regular meetings around late March and late October. TimeZonar's world clock also shows a notice two weeks before any of your cities changes its clocks. The daylight saving time guide lists the dates for each region.

If you need to check a single time by hand, see how to convert time zones. If you're the one traveling, read traveling across time zones.

1. 1.Gulf News, UAE weekend change: emirates announce new work week. The UAE's move to a Saturday and Sunday weekend in 2022.
2. 2.IETF, RFC 5545: Internet Calendaring and Scheduling (iCalendar). Calendar events carrying a time zone, and how they behave across clock changes.
3. 3.U.S. Department of Transportation, Daylight Saving Time. US change dates.
4. 4.EUR-Lex, Directive 2000/84/EC on summer-time arrangements. EU change dates.