Why do the US and Europe change clocks on different dates?

The US moves its clocks on the second Sunday of March and the first Sunday of November. The European Union and the United Kingdom move theirs on the last Sunday of March and the last Sunday of October. The two rules do not line up, so the regions disagree for a short time.

How long does the clock gap last?

In spring it lasts two to three weeks, depending on the year, and in autumn it lasts one week. The exact dates for the current and next year are listed in this guide.

What changes during the gap?

New York is 4 hours behind London instead of the usual 5. Both sessions keep their local hours, so the London-New York overlap starts an hour earlier in London time and lasts an hour longer.

The US and Europe Clock Gap: Why the London-New York Overlap Shifts

Most of the year, New York is five hours behind London. For a short stretch every spring and again every autumn, it is only four. That difference comes from a quirk in the calendar: the United States and Europe both use daylight saving time, but they switch on different weekends.

The rule on each side

The United States moves its clocks forward on the second Sunday of March and back on the first Sunday of November. The United Kingdom and the European Union move forward on the last Sunday of March and back on the last Sunday of October.

In spring, the US switches first, so for a while New York is on summer time while London is still on winter time. In autumn, Europe switches back first, and for a week London is on winter time while New York is still on summer time. In both cases the two regions are one hour closer together than usual.

What it does to the overlap

Each forex session keeps its own local hours. The London session runs 8:00 AM to 5:00 PM London time and the New York session runs 8:00 AM to 5:00 PM New York time, so the clock gap decides how much of those two days is shared.

During the gap, New York opens an hour earlier relative to London than usual. The London-New York overlap therefore starts an hour earlier in London time and lasts an hour longer than normal. Once the second region changes its clocks, the usual hours return.

The same thing happens to anything else tied to both regions, such as the opening of US stocks compared with the London afternoon. If you schedule your day around the overlap, the weeks inside the gap are the ones that need a second look.

Exact dates for this year and next

The dates below are read from the same timezone data the live pages use, so they update automatically when the calendar year changes.

2026

Spring: The United States changes its clocks on March 8, and the other region follows on March 29. The gap lasts 21 days.
Autumn: Europe changes its clocks on October 25, and the other region follows on November 1. The gap lasts 7 days.

2027

Spring: The United States changes its clocks on March 14, and the other region follows on March 28. The gap lasts 14 days.
Autumn: Europe changes its clocks on October 31, and the other region follows on November 7. The gap lasts 7 days.

How the site handles it

Every schedule on timenow.dev is stored with a timezone identifier such as America/New_York or Europe/London, never with a fixed offset. The browser's own timezone data decides when each region changes, so the live status and countdown are correct on both sides of a switch. When the gap is active, the London-New York overlap page shows a notice at the top.

Visitors in other timezones

If you live somewhere that never changes its clocks, such as India or Japan, the overlap still moves in your local time whenever either region changes. The shift is an hour at a time, which is why the same overlap can sit at one local time in January, another in April, and a third in July. Set your timezone from the header on any page and the schedule tables convert for you.

For deeper background on how the sessions fit together, read forex sessions explained. Hours here are for reference only. Verify with the official exchange before trading.