The source of the confusion
Time zone mistakes are rarely about arithmetic alone. They come from small assumptions: that “3 p.m.” means the same thing to everyone, that a colleague’s calendar adjusts automatically, or that the clocks change on the same date everywhere. Each assumption can cause a missed meeting or a deadline that means different things to different people.
A few shared conventions remove most of the risk. They are cheap to adopt and most useful when everyone follows them.
Always state the zone
Never write a time without saying where it applies. “Thursday at 10:00” is incomplete. Better:
- “Thursday 10:00 in London (UTC)” or
- “Thursday 10:00 Eastern, which is 16:00 in Berlin.”
Choosing one anchor zone for the team, often the zone of the headquarters or UTC, gives everyone a reference point. When you propose a time, also give it in the recipient’s local time if you know it. Most calendar tools convert invitations automatically, but written messages and documents do not, so spell it out.
Also name the date, not just the weekday, when people are far apart. Because of the difference in hours, “tomorrow” for you might still be “today” for a colleague on the other side of the world.
Use numeric and unambiguous formats
The 24-hour clock avoids a.m./p.m. confusion. Writing dates with the month as a word, such as “14 March” rather than “3/14” or “14/3,” avoids mix-ups between regional formats. These details seem small but are a frequent source of misunderstanding between countries.
Know each person’s working hours
Scheduling is easier when working hours are visible. Ask each team member to set their hours in their calendar and list their location or zone in a shared profile. Then use the scheduling view to find a window where everyone is within reasonable hours. The conventions for availability described in the article on shared calendars apply here.
Keep in mind that “reasonable hours” varies. Someone may welcome an early start; another may have family commitments in the evening. Ask instead of assuming.
Find the overlap, and check how small it is
Take the working hours of everyone involved and look for the shared window. Here is a hypothetical example: if one group works 09:00 to 17:00 and another is eight hours ahead working 09:00 to 17:00 in their own time, the first group’s 09:00 is the second group’s 17:00, so the overlap is essentially nil. With a five-hour difference, the same workdays overlap for about three hours: when it is 09:00 for the earlier group, it is 14:00 for the later one, so the shared period runs from 09:00 to 12:00 in the earlier zone.
When the overlap is tiny, it becomes a scarce resource. Spend it on conversations that really need real-time discussion and handle everything else in writing, as described in asynchronous work.
Rotate the inconvenient slot
If the only workable time is early for one group and late for another, avoid making the same people bend every time. Alternate the burden: one week the meeting is early for group A, the next it is late for group B. Some teams hold two versions of a recurring meeting, or record one session and discuss it in writing with those who could not attend. Fairness here has a direct effect on morale, so it is worth stating the rotation openly.
Beware daylight saving time
Not all regions change clocks, and those that do change on different dates. The result is that the time difference between two cities can shift by an hour for a few weeks each year, even though neither team changed its schedule. Some regions do not observe daylight saving at all.
Practical steps:
- Create recurring meetings in a calendar that handles zones, and set the event in one specific zone.
- Check the meetings scheduled around the dates when clocks change, and tell the team in advance.
- Be careful about which zone a recurring event is anchored to, because anchoring to a different zone shifts the apparent local time for some participants.
Because rules differ and change, verify with a reliable time converter or your calendar’s own display rather than relying on memory.
Deadlines need zones too
A deadline of “end of day Friday” is vague when people are in several places. State the exact time and zone, for example “Friday 17:00 UTC.” If the work is handed over between regions, write the handoff so it fits each group’s working day. Where precision matters less, a rule such as “by the start of your Monday” is clear for everyone, but say so.
Reduce the number of live meetings
The more regions involved, the stronger the case for shortening or removing meetings. Share agendas and materials beforehand so the live session can be brief. Send notes and decisions afterward, since someone will have missed the call. The habits in the guide on running better meetings, and in the article on writing a meeting agenda, matter even more when time is scarce.
Put the details in the invitation
An invitation for an international meeting might include:
- Date and time in the anchor zone, and ideally in major attendee zones.
- The purpose and agenda.
- Who is required and who is optional.
- How to join, and what to do if a person cannot make it.
- Where notes and recordings will be stored.
Handy tools and habits
You do not need specialized software. A world clock view, a calendar that shows multiple zones side by side, and a meeting planner that lists overlap are all helpful. Some people add a second or third zone to their calendar display permanently. Others keep a small table in the team wiki listing each member’s city, zone, and typical hours.
Treat it as a team agreement
The most effective approach is to write a short set of guidelines, agree on them together, and revisit them when the team changes. They might say which zone is the anchor, how far in advance meetings are scheduled, which hours are off limits, and how rotation works. The details will differ by team, but the principle is the same: remove guesswork, share the inconvenience, and make the times impossible to misread.