Why your recurring meeting moves by an hour twice a year
The US changes its clocks three weeks before the EU. For those three weeks, every standing transatlantic meeting is in the wrong slot — and almost nobody notices until someone misses it.
The three-week gap
The United States moves to daylight saving on the second Sunday in March. The European Union moves on the last Sunday in March. In 2026 that is a gap of three weeks during which the usual five-hour difference between London and New York becomes four.
In autumn the gap runs the other way and is shorter: the EU falls back on the last Sunday in October, the US on the first Sunday in November, leaving one week of mismatch.
What it does to a meeting
Take a standing call agreed as 3pm London, 10am New York.
| Period | London | New York | Gap |
|---|---|---|---|
| January | 3:00pm GMT | 10:00am EST | 5 hours |
| Mid-March | 3:00pm GMT | 11:00am EDT | 4 hours |
| April | 3:00pm BST | 10:00am EDT | 5 hours |
For three weeks, either London joins at 2pm or New York joins at 11am. Whichever way the calendar entry was written, one side is wrong.
Why it goes unnoticed
Because it self-corrects. By April the gap is back to five hours and the meeting is fine again, so nobody investigates. The three weeks of confusion get attributed to individuals forgetting rather than to a structural mismatch.
The fix
Send a calendar invitation instead of agreeing a clock time in writing. A calendar entry stores an absolute instant plus an organiser zone, and each attendee's client renders it in their own zone — including through a transition. An email saying "every Tuesday at 3pm" carries no zone information at all.
- Create the recurring event once, from a calendar client, with the organiser's zone attached.
- Avoid re-creating it each quarter, which is when fixed-time errors creep in.
- Put a reminder in late March and late October to sanity-check standing invites.
The exact dates, year by year
| Region | Clocks forward | Clocks back |
|---|---|---|
| United States and Canada | Second Sunday in March | First Sunday in November |
| European Union and UK | Last Sunday in March | Last Sunday in October |
| Australia (south-east) | First Sunday in October | First Sunday in April |
Two mismatched windows fall out of that table every year: about three weeks in March when the US has moved and Europe has not, and about one week between late October and early November when Europe has gone back and the US has not.
Which pairs are affected, and which are not
- New York ↔ London. Affected. Normally five hours; four for three weeks in spring.
- New York ↔ Chicago. Not affected. Both change on the same day, so the gap stays one hour.
- London ↔ Paris. Not affected. The EU and UK move together.
- New York ↔ Phoenix. Affected, because Arizona does not change at all.
- London ↔ Mumbai. Affected. India never changes, so the gap moves when the UK does.
How to audit a calendar quickly
- Filter your calendar to recurring events with external attendees.
- For each, check whether the attendees span a pair from the affected list.
- Open the event and confirm it has an organiser time zone attached — not just a clock time.
- Re-create anything created from a plain-text agreement; that is where fixed times hide.
The one habit that fixes it permanently
Create recurring events in a calendar client with the organiser's zone set explicitly, and never re-type the time when the series needs extending. The calendar stores an instant plus a zone rule; a human retyping "3pm" stores neither.
Filed under Scheduling · Tags: daylight saving, recurring meetings, calendar. Figures verified against the official definitions — see our editorial policy.