Compare daylight saving transitions for a workshop

You set a workshop time that works for everyone, then daylight saving time changes and someone arrives an hour early or late. This often happens when attendees live in places that change clocks on different dates, or do not change clocks at all.

Use the World Clock to check participant locations and their local times. Then compare the workshop date with each location’s clock-change dates before you send the invite.

Compare the workshop time across locations

1. Open the World Clock and look up the cities where attendees will join from. Use the city or time-zone display to confirm you have the right location, especially if a country has regions with different clock rules.
2. Choose one reference time for the invitation, such as 10:00 a.m. in the host’s city. Write down the date and the host’s time zone, not just the time. A date and zone make the reference unambiguous.
3. Check the time difference for the actual workshop date. If the World Clock offers a way to select a date, use it. If it shows current times only, check the date-aware time conversion in your calendar before relying on the current offset.
4. Repeat the comparison for a date shortly before and shortly after each location’s clock change. Note the local time and calendar date for every city, then put the confirmed time in the invite.

For a recurring workshop, check every session that falls near a clock change. A weekly meeting can keep the same time in the host’s city while shifting by an hour for some attendees.

What the comparison means

One location is an hour earlier or later than expected

The locations may have changed clocks on different dates. For example, under current rules, the United States changes clocks in March and November, while the United Kingdom changes in March and October. In the short periods when only one has changed, the time difference between New York and London shifts by an hour. Check the offset for the workshop date rather than assuming the usual difference applies.

The local time matches, but the date is different

Some locations are far enough apart that a morning meeting in one city falls on the previous evening elsewhere. Include the local date in the invite, especially for attendees near the International Date Line. A time without a date can point to two different sessions.

The difference stays the same through the transition

Both locations may change clocks on the same date, or one may not observe daylight saving time. Do not assume that every city in a country follows the same rule. For example, most of Arizona and Hawaii do not observe daylight saving time, while other US states do.

The difference changes by more than you expected

Check that you selected the correct city and the correct date. Some regions have local rules that differ from nearby areas. In countries in the Southern Hemisphere, daylight saving changes often happen in different months from those in North America and Europe, and not every region observes it.

How to avoid a scheduling mistake

1. Use a named time zone. Write “10:00 a.m. Eastern Time” instead of “10:00 a.m. EST.” EST means a specific standard-time offset, while a regional time zone can switch between standard and daylight time during the year.
2. Set the event on the correct date. When creating a calendar invite, enter the workshop’s date and time in the host’s intended time zone. Calendar apps can convert that event for attendees, but a wrong date or zone will still produce a wrong conversion.
3. Check dates on both sides of a transition. If the workshop repeats weekly, compare one session before the change and one after it. Do this for the host’s location and for attendees whose regions change clocks on different dates.
4. Share a second reference. Include the host city and a link to the calendar event. For a small group coordinating by email, state one or two attendee locations with their local date and time so people can spot a mismatch.
5. Recheck after a rule change. Time-zone rules can be changed by governments. If an event is months away, confirm the conversion again closer to the date rather than reusing an old offset.

If you are planning a call across several regions, plan the call around each attendee’s local time. For more on why a city’s meeting time can change when clocks move, see why meeting times change between cities.

Why the shift does not happen everywhere at once

Daylight saving time is a local calendar rule, not a worldwide change made on one day. A region may move its clocks forward in spring and back in fall, use different transition dates from a nearby region, or keep the same clocks all year. Some countries in the Southern Hemisphere also have their summer months at the opposite time of year from those in the Northern Hemisphere.

That is why the live clock is helpful for checking what time it is now, but it cannot by itself guarantee a future workshop time. Compare the exact date, the correct city and the location’s rule for that date. For recurring sessions, keep the invite attached to a named time zone rather than copying a fixed UTC offset from one week to the next.