The practical mechanics of scheduling
Most time zone errors are not conceptual. They are the daylight saving change nobody accounted for.
Time zone confusion in distributed teams is rarely about understanding what a time zone is. It is about a handful of specific mechanical traps that recur reliably. For broader context on planning work across time zones, Timeanddate Meeting Planner is a useful reference.
Daylight saving is the main one
Regions change clocks on different dates, and some do not change at all. For several weeks a year, the gap between two cities is different from what everyone has memorised, and a recurring meeting silently moves for half the participants.
The defences are ordinary: schedule in a calendar that stores the time zone rather than a fixed local time, put the changeover dates in the shared calendar, and check recurring meetings in the fortnight around each transition. For a practical software-side reference on time rounding and payroll scheduling, 7-minute rule for payroll adds useful detail.
When Europe and North America shift, Australia and New Zealand are moving the other way. Twice a year the gap changes by two hours, not one.
Write times with the zone attached
Never write a bare time in a distributed team. '14:00' means nothing; '14:00 UTC' or '14:00 CET / 08:00 EST' is unambiguous.
Where a canonical reference is useful, UTC is the sensible choice — but only if everyone understands it means UTC and not 'London time', which is only equal to UTC in winter. That specific confusion causes more misses than any other.
Give dates as well as times
Across a wide spread, 'tomorrow' and 'end of day' are ambiguous, and 'Friday' can be Saturday for someone. Deadlines should carry a date and a zone.
The same applies to numeric date formats: 03/04 is two different days depending on the reader's country. Write the month as a word.
Publish a schedule in local time
For anything involving several regions — a launch, a maintenance window, a conference — publish the schedule in every relevant local time rather than expecting people to convert.
Conversion errors made by a tired person at the wrong end of the day are the norm, not the exception, and the cost of publishing three columns instead of one is nothing.
Respect the local calendar
Public holidays differ, and a team that works to one country's calendar will schedule important things into other people's holidays repeatedly.
A shared calendar with everyone's public holidays takes an hour to set up once and prevents an entire category of friction — including the specific one where someone quietly works a national holiday because a deadline was set without knowing.