Avoiding daylight saving mistakes when scheduling international calls

Why one fixed number per colleague stops working

The US, the UK, the EU and Australia all change their clocks on different dates, and India, Japan, Singapore and most of Asia never change at all. A time gap that is correct this week can be an hour off three weeks from now.

Most people carry a single number in their head for each person they work with. London is five hours ahead of New York. Bengaluru is nine and a half hours ahead. Those numbers are each right for part of the year and wrong for the rest.

The trouble starts when one country moves its clocks and the other does not. A recurring invite still says 9:00, nobody’s calendar raises a flag, and one person dials in an hour early or an hour late. Because the change happens on a weekend, the first missed meeting is usually on a Monday, when everyone is busiest and least likely to double check.

The clock change calendar for the regions that matter most

The United States and most of Canada move clocks forward on the second Sunday in March and back on the first Sunday in November. The UK and the European Union move forward on the last Sunday in March and back on the last Sunday in October. In the southern hemisphere the seasons run the other way, so Sydney and Melbourne go back on the first Sunday in April and forward on the first Sunday in October. India Standard Time is UTC+5:30 all year with no change.

Two exceptions are worth keeping in mind. Arizona, outside the Navajo Nation, stays on Mountain Standard Time all year, so in summer it lines up with California. And Asia’s big business hubs, including India, Japan, Singapore and China, do not observe daylight saving, which means every gap between them and the US or Europe moves twice a year.

The official dates come from each government’s law. This page is about what they do to your calendar. For this fall’s change, see the November 2026 daylight saving recap.

The mismatch weeks between the US and Europe

The most dangerous stretches of the year are the weeks between the American and European change dates. In 2027 there are two of them for New York and London.

• March 14 to March 27: New York has moved to Eastern Daylight Time (UTC−4) while London is still on Greenwich Mean Time (UTC+0). The usual five hour gap shrinks to four.
• October 31 to November 6: London has gone back to GMT while New York is still on EDT, so the gap is again four hours.

Paris, Berlin and the rest of the EU follow the same dates as London, so a New York and Berlin call drifts in the same way, from six hours to five. Here is a team that meets every Wednesday at 9:00 AM New York time:

London’s time moved twice in a month. Bengaluru’s moved once and then stayed put until November.

How India’s fixed clock shifts every other gap

Because India never changes, the only thing that moves the gap to India is the other country. A call booked at a fixed New York time lands an hour earlier in India from mid March and an hour later from early November. Teams in India often notice first, because their evening call suddenly runs into dinner or finishes before the commute.

A routine that prevents most mistakes

1. Name the anchor. Decide whose clock a recurring meeting follows and write it into the invite as plain text, for example “9:00 AM New York time”. Calendars store a recurring event in one time zone and let everyone else’s time float, so naming the anchor tells people which side will move.
2. Write the city plus ET, not “EST” in July. “3 PM EST” in July describes a time no New York clock shows, and a colleague who converts it literally as UTC−5 arrives an hour late. “3 PM ET” or “3 PM New York” is never wrong.
3. Always include the date. “3 PM ET” is ambiguous across a clock change, but “3 PM ET on Tuesday, March 16” is not. For someone in India or Australia the date matters twice over, because their Wednesday morning can be your Tuesday evening.
4. Set two yearly reminders. One for the second week of March and one for the last week of October, to review every recurring call that includes people abroad. Those two windows cover the US, UK and EU changes.
5. Avoid 2:00 AM local on change nights. In the fall some wall clock times happen twice, and in the spring some never happen. It rarely matters for business calls, but it does for overnight deploys and automated jobs.
6. Send a link, not a number. A link that shows the time in each reader’s own zone takes the arithmetic off their plate.

How MeetETA handles the date for you

MeetETA is built on the IANA time zone database and computes the offset for the date you type, not for today. On the converter you can type “2026-11-05 09:00 ET” and see the result on that date. If you type “3 PM EST” in the middle of summer, it treats that as New York local time and notes that you probably mean EDT. A time in the repeated hour when clocks go back, or one that never exists when they go forward, is flagged, and when a clock change is coming within 14 days for the places you are looking at, you get a heads up.

For recurring calls with three or more cities, add them all to the meeting planner and look at one date on each side of a change. If the slot still works in both seasons, you are safe for the year. For the full method, see how to find a meeting time across time zones, and for exact conversions, how to convert a date and time across time zones.

Common questions