Every March our weekly call moves and nobody knows why

Somebody joins late. Somebody else was there twenty minutes early and assumed they had the wrong week. By the third occurrence people have started asking in the chat whether the time changed, and nobody who could answer is quite sure.

Then it stops, and everyone forgets about it until next year.

Why it fixes itself, which is the real problem

If this broke permanently, someone would investigate and fix it.

Instead it breaks for about three weeks and then resolves on its own — because the second region eventually catches up. By the time anybody has escalated it, the symptom is gone and the ticket gets closed as unreproducible.

So it recurs every year, costs a few confusing weeks each time, and never gets diagnosed.

What is actually happening

The US changes its clocks on the second Sunday in March. The UK and EU wait until the last Sunday in March. In 2026 that is 2026-03-08 and 2026-03-29 — three weeks apart.

During those weeks, the US has sprung forward and Europe has not, so the transatlantic gap is four hours instead of five. A meeting written as a fixed local time on both sides cannot be right for both.

In autumn it happens again, reversed and shorter: Europe falls back on 2026-10-25, the US on 2026-11-01.

If one side is somewhere that never changes clocks — India, Arizona, most of Asia — then the meeting moves twice a year and that side did nothing at all.

The fix is in how the invite was created

Almost always, the meeting was set up as a time typed into the description, or as an event anchored to a fixed offset rather than a zone.

A recurring event created properly — with a zone attached, not just an hour — re-resolves for each occurrence through the time zone database, which encodes both regions' rules including the gap weeks. It will be correct without anyone thinking about it.

Three things to do:

Recreate the series with a zone. Pick the zone of whoever must be present, and say which one you picked.

Put both local times in the title, so drift is visible on sight rather than after someone misses it:

Weekly sync — 16:00 London / 11:00 New York

Stop restating the time in the body. The description does not convert. When it disagrees with the event, the description is the one that is wrong, and it is the one people read.

Diary the four dates

2026-03-08, 2026-03-29, 2026-10-25, 2026-11-01.

Those are the only four moments in the year when a standing cross-region arrangement can silently move. A five-minute check on each is the entire preventative measure.

Related: For three weeks a year the US and Europe are out of step · What DST does to a recurring calendar invite

Figures on this page are computed from the IANA time zone database. Last generated 2026-08-18.