Avoiding daylight saving mistakes when scheduling international calls

Nearly every daylight saving mistake comes from converting a meeting time for today instead of for the day the meeting actually happens. 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. The fix is simple to state: put a date on every time you send, anchor recurring calls to one city, and use a converter that looks up the offset for that specific date.

This guide walks through why the errors happen, the exact dates that cause trouble, and a routine that catches them before anyone shows up to an empty call.

Why one fixed number per colleague stops working

Most people carry a single number in their head for each person they work with. London is five hours ahead of New York. Bangalore 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.

Region	Clocks go forward	Clocks go back	2027 dates
United States and most of Canada	2nd Sunday in March	1st Sunday in November	March 14 and November 7
UK	Last Sunday in March	Last Sunday in October	March 28 and October 31
European Union	Last Sunday in March	Last Sunday in October	March 28 and October 31
Sydney and Melbourne	1st Sunday in October	1st Sunday in April	Back April 4, forward October 3
India	No change	No change	IST is UTC+5:30 all year

A couple of local 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 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.

From March 14 to March 27, New York has already 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. From October 31 to November 6 the same thing happens in reverse: London has gone back to GMT, New York is still on EDT, and 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.

Here is how that plays out for a team that meets every Wednesday at 9:00 AM New York time.

On March 10, 2027, 9:00 AM EST is 2:00 PM in London and 7:30 PM in Bangalore. A week later, on March 17, the US has switched, and 9:00 AM EDT is 1:00 PM in London and 6:30 PM in Bangalore. By April 7, London has caught up with British Summer Time, so 9:00 AM EDT is 2:00 PM in London again, while Bangalore stays at 6:30 PM until November. London's time moved twice in a month. Bangalore's moved once and then stayed put.

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. New York is 10 hours 30 minutes behind India in winter and 9 hours 30 minutes behind in summer. London is 5 hours 30 minutes behind India in winter and 4 hours 30 minutes behind in summer. Los Angeles is 13 hours 30 minutes behind in winter and 12 hours 30 minutes behind in summer.

That means 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.

Pair	Summer gap	Winter gap	What moves it
New York and London	5 hours	5 hours	4 hours during the mismatch weeks
New York and India	9 h 30 m	10 h 30 m	US change dates
London and India	4 h 30 m	5 h 30 m	UK change dates
Los Angeles and India	12 h 30 m	13 h 30 m	US change dates

A routine that prevents most mistakes

The habits that work are not complicated. They just need to be applied every time.

Start by deciding 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.

Always include the date with a time. "3 PM ET" is ambiguous across a clock change, but "3 PM ET on Tuesday, March 16" is not. If you are writing to someone in India or Australia, the date matters twice over, because their Wednesday morning can be your Tuesday evening.

Put two reminders in your own calendar each year, 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.

Stay away from times near 2:00 AM local on the nights clocks change. In the fall some wall clock times happen twice, and in the spring some never happen at all. It rarely matters for business calls, but it does matter for overnight deploys and automated jobs.

Finally, send a link instead of a number when you can. A link that shows the time in each reader's own zone takes the arithmetic off their plate entirely.

How MeetETA handles the date for you

MeetETA is built on the IANA time zone database, the same data your operating system uses, and it computes the offset for the specific date you type rather than for today. On meeteta.com/convert you can type something like "2026-11-05 09:00 ET" and see the result on that date, with Eastern already back on standard time.

It is forgiving about the way people really write times. If you type "3 PM EST" in the middle of summer, MeetETA treats it as New York local time and notes that you probably mean EDT. If you enter a time that falls in the repeated hour on the night clocks go back, such as 1:30 AM, it explains the ambiguity and lets you choose the first or second occurrence. A spring time that never exists, like 2:30 AM on the change night, is flagged as well. And when a clock change is coming within the next 14 days for the places you are looking at, MeetETA shows a heads up.

To send a time, use the share button on the converter. It creates a link that opens the moment in each viewer's own time zone, with an option to add it to their calendar. This one shows 3 PM New York time on October 15, 2026 to someone in India:

/t?at=2026-10-15T19:00:00Z&from=America/New_York&to=Asia/Kolkata

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.

Where things stand after the November 2026 change

US clocks went back on Sunday, November 1, 2026, one week after the UK and EU switched on October 25. New York is once again 5 hours behind London and 10 hours 30 minutes behind India, and it stays that way until March 14, 2027. Our guide to daylight saving time ending in November 2026 covers that switch in more detail, including the week when the gap to Europe was briefly four hours.