Time Zones and Calling Home

Time zones cause two problems that look the same and are not. One is jet lag, which is your body being in the wrong time. The other is coordination, which is arranging a call that is reasonable at both ends. This guide is about the second, and it is mostly arithmetic done once, in advance, and written down.

What You Need to Know

Find the overlap

The useful output is a window: a period when both ends are awake and free. For most trips there is a few-hour band, usually early morning at one end and evening at the other, and finding it once removes the daily negotiation. Write it down as a sentence in both zones, for example "eight in the evening for me is ten in the morning for you", and give that sentence to whoever you are coordinating with.

Always name the zone

Agreeing "we will speak at nine" between two countries is how calls get missed. State the zone, or state both times. This applies with equal force to a work meeting, a family call and a group briefing, and it is the single most common cause of a missed international call.

The complications worth knowing

• Daylight saving is not universal and where it exists the changeover dates differ. The gap between two cities can change by an hour in the middle of a trip without either end doing anything.
• Not every offset is a whole hour. Several places sit on a half-hour or three-quarter-hour offset, which a mental calculation quietly gets wrong.
• Some large countries use one zone throughout and some use several, so "the time in that country" may not be a single answer.
• The date changes too. An evening call from one side can be the following morning on the other, which matters for anything with a deadline.

Practical handling

Set your phone to destination time when you board and think in it from then on, which also helps the body-clock problem covered in Hydration and Jet Lag. Add a second clock for home so you can see both without arithmetic. And when you send a calendar invitation rather than a message, most software handles the conversion for everyone, which removes the error entirely.

What to Do Before Your Trip

• Calculate the offset for every country on the itinerary.
• Agree the call window in both time zones, in writing.
• Check for a daylight saving change during your dates.
• Add a second clock for home on your phone.
• Send calendar invitations rather than agreeing times in messages.

Important Considerations

A multi-country itinerary can cross several zones, and the traveler is the one who has to keep track. Publish the itinerary in local time throughout, label it as such, and be explicit at each border. Groups miss transport over this rather than over anything more interesting.

Anything with a deadline deserves care: a work obligation, a visa appointment, a check-in window, a flight change. Convert it deliberately and write both times down, because these are the cases where being an hour out has a cost.

Be considerate about the other end. A call that suits you at nine in the evening may land in the middle of someone’s night, and people will accept it once rather than say so. Agreeing the window in advance protects them from having to.

Tips for Group Travelers

• Publish all times in local time, and label them.
• Announce the change at each border.
• Remind people to change their phones, and their watches.
• Give families the overlap window so they do not call at three in the morning.
• Use calendar invitations for anything with a deadline.

Common Mistakes to Avoid

• Agreeing a time without naming the zone.
• Assuming a whole-hour offset.
• Forgetting daylight saving changes mid-trip.
• Forgetting the date can differ.
• Publishing a group itinerary in two time zones at once.

Frequently Asked Questions

How do I find a good time to call home?

Work out the overlap once and write it as a sentence in both time zones, then share that sentence. For most trips there is a band of a few hours where both ends are awake, usually morning at one end and evening at the other, and fixing it in advance removes the daily negotiation.

Do all countries change their clocks?

No. Daylight saving is used in some countries and not others, and where it is used the changeover dates differ. That means the gap between two cities can change by an hour partway through a trip without either party doing anything, which is worth checking against your dates.

Are all time zones a whole number of hours apart?

No. Several places sit on a half-hour or three-quarter-hour offset from their neighbors, which is exactly the case a mental calculation gets wrong. Check the actual offset rather than assuming, particularly for anything with a deadline.

Related Travel Tips

• Phones, technology and connectivity, the section this guide belongs to.
• Staying Connected With Family at Home.
• Hydration and Jet Lag. The body-clock half.
• Long-Haul Flight Tips. Where the shift begins.

Plan Your Trip With LABUSA Travel

A multi-country itinerary crossing several zones is easier to follow when it is published in local time throughout and the changes are marked. LABUSA Travel builds itineraries that way.

Talk with a LABUSA Travel advisor about a trip you are considering, or browse our destination guides for a specific country.

Verify Before You Travel

Local time, offsets and daylight saving dates are set nationally and change; confirm them against a current source for your travel dates. Country information, including local conditions, is published by the U.S. Department of State and independently by the U.K. FCDO.